diff --git a/accessibility-checker-engine/help-v4/common/help.css b/accessibility-checker-engine/help-v4/common/help.css
index 1f263f4a7..0db9f74b4 100644
--- a/accessibility-checker-engine/help-v4/common/help.css
+++ b/accessibility-checker-engine/help-v4/common/help.css
@@ -29,7 +29,7 @@ bx-list-item>code, p>code, td>code {
     position: relative;
 }
 
-.toolhelp a {
+.toolHelp a {
     color: var(--cds-link-primary)
 }
 
@@ -38,7 +38,7 @@ bx-list-item>code, p>code, td>code {
 }
 
 .toolHelp .toolHead h3 {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 600;
     font-size: 16px;
@@ -46,7 +46,7 @@ bx-list-item>code, p>code, td>code {
 }
 
 .toolHelp .toolHead .issueLevel {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 400;
     font-size: 12px;
@@ -54,7 +54,7 @@ bx-list-item>code, p>code, td>code {
 }
 
 .toolHelp .toolHead #ruleMessage {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 600;
     font-size: 16px;
@@ -64,7 +64,7 @@ bx-list-item>code, p>code, td>code {
 }
 
 .toolHelp .toolHead #groupLabel {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 400;
     font-size: 12px;
@@ -73,7 +73,7 @@ bx-list-item>code, p>code, td>code {
 
 /* productive-heading-03 */
 .toolHelp .toolMain h3 {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 600;
     font-size: 16px;
@@ -88,7 +88,7 @@ bx-list-item>code, p>code, td>code {
 
 /* productive-heading-03 */
 .toolHelp .toolSide h3 {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     font-style: normal;
     font-weight: 600;
     font-size: 16px;
@@ -101,7 +101,7 @@ bx-list-item>code, p>code, td>code {
     }
 }
 body {
-    font-family: 'IBM Plex Sans', sans-serif;
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
     color: var(--cds-text-primary);
     background-color: var(--cds-ui-background);
 }
@@ -114,7 +114,7 @@ body {
 }
 
 .toolHelp p {
-    font-family: 'IBM Plex Sans';
+    font-family: 'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
 font-style: normal;
 font-weight: 400;
 font-size: 14px;
@@ -156,7 +156,7 @@ letter-spacing: 0.16px;
 
 .toolHelp .toolSide {
     padding: 16px 16px 16px 32px;
-    background-color: var(--cds-ui-background);;
+    background-color: var(--cds-ui-background);
     color: var(--cds-text-primary);
     border-top: solid var(--cds-text-primary) 1px;
 }
@@ -193,3 +193,76 @@ bx-code-snippet[type="multi"]::after {
 #ruleInfo p {
     font-size: 14px;
 }
+
+mark-down table tbody tr:hover {
+    background: var(--cds-layer-hover);
+}
+mark-down table tbody tr:hover td, mark-down table tbody tr:hover th {
+    background: var(--cds-layer-hover);
+    -webkit-border-after: 1px solid var(--cds-layer-hover);
+    border-block-end: 1px solid var(--cds-layer-hover);
+    -webkit-border-before: 1px solid var(--cds-layer-hover);
+    border-block-start: 1px solid var(--cds-layer-hover);
+    color: var(--cds-text-primary,#161616);
+}
+
+mark-down table {
+    margin-top: 1rem;
+    width: 100%;
+}
+
+@media (min-width: 66rem) {
+    mark-down table {
+        max-width: 66.66%;
+    }
+}
+
+mark-down table thead {
+    font-size: var(--cds-heading-compact-01-font-size,0.875rem);
+    font-weight: var(--cds-heading-compact-01-font-weight,600);
+    line-height: var(--cds-heading-compact-01-line-height,1.28572);
+    letter-spacing: var(--cds-heading-compact-01-letter-spacing,0.16px);
+    background-color: var(--cds-layer-accent);
+}
+
+mark-down table tr {
+    border: none;
+    block-size: 3rem;
+    inline-size: 100%;
+}
+
+mark-down table th {
+    background-color: var(--cds-layer-accent);
+    color: var(--cds-text-primary,#161616);
+    -webkit-padding-end: 1rem;
+    padding-inline-end: 1rem;
+    -webkit-padding-start: 1rem;
+    padding-inline-start: 1rem;
+}
+
+mark-down table td, mark-down table th {
+    text-align: start;
+    vertical-align: middle;
+}
+
+mark-down table tbody {
+    font-size: var(--cds-body-compact-01-font-size,0.875rem);
+    font-weight: var(--cds-body-compact-01-font-weight,400);
+    line-height: var(--cds-body-compact-01-line-height,1.28572);
+    letter-spacing: var(--cds-body-compact-01-letter-spacing,0.16px);
+    background-color: var(--cds-layer);
+    inline-size: 100%;
+}
+
+mark-down table td, mark-down table tbody th {
+    background: var(--cds-layer);
+    -webkit-border-after: 1px solid var(--cds-border-subtle);
+    border-block-end: 1px solid var(--cds-border-subtle);
+    -webkit-border-before: 1px solid var(--cds-layer);
+    border-block-start: 1px solid var(--cds-layer);
+    color: var(--cds-text-secondary,#525252);
+    -webkit-padding-end: 1rem;
+    padding-inline-end: 1rem;
+    -webkit-padding-start: 1rem;
+    padding-inline-start: 1rem;
+}
\ No newline at end of file
diff --git a/accessibility-checker-engine/help-v4/en-US/IBMA_Color_Contrast_WCAG2AA_PV.html b/accessibility-checker-engine/help-v4/en-US/IBMA_Color_Contrast_WCAG2AA_PV.html
index 0d822537c..0f53f21ce 100644
--- a/accessibility-checker-engine/help-v4/en-US/IBMA_Color_Contrast_WCAG2AA_PV.html
+++ b/accessibility-checker-engine/help-v4/en-US/IBMA_Color_Contrast_WCAG2AA_PV.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_ArticleRoleLabel_Implicit.html b/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_ArticleRoleLabel_Implicit.html
index e9a5df9dd..c7443179e 100644
--- a/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_ArticleRoleLabel_Implicit.html
+++ b/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_ArticleRoleLabel_Implicit.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_GroupRoleLabel_Implicit.html b/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_GroupRoleLabel_Implicit.html
index 680d627f0..1c6cc6d3d 100644
--- a/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_GroupRoleLabel_Implicit.html
+++ b/accessibility-checker-engine/help-v4/en-US/Rpt_Aria_GroupRoleLabel_Implicit.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/a_target_warning.html b/accessibility-checker-engine/help-v4/en-US/a_target_warning.html
index a8e84ec42..06d957a07 100644
--- a/accessibility-checker-engine/help-v4/en-US/a_target_warning.html
+++ b/accessibility-checker-engine/help-v4/en-US/a_target_warning.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/a_text_purpose.html b/accessibility-checker-engine/help-v4/en-US/a_text_purpose.html
index ec4e461cc..f24c8369f 100644
--- a/accessibility-checker-engine/help-v4/en-US/a_text_purpose.html
+++ b/accessibility-checker-engine/help-v4/en-US/a_text_purpose.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/applet_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/applet_alt_exists.html
index eb0ae23ac..e5a9986b6 100644
--- a/accessibility-checker-engine/help-v4/en-US/applet_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/applet_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/application_content_accessible.html b/accessibility-checker-engine/help-v4/en-US/application_content_accessible.html
index 0442fa3ba..1d0ab784f 100644
--- a/accessibility-checker-engine/help-v4/en-US/application_content_accessible.html
+++ b/accessibility-checker-engine/help-v4/en-US/application_content_accessible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/area_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/area_alt_exists.html
index c99b3c081..6edbd11f0 100644
--- a/accessibility-checker-engine/help-v4/en-US/area_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/area_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_accessiblename_exists.html b/accessibility-checker-engine/help-v4/en-US/aria_accessiblename_exists.html
index 4b91c7d9e..3bda66957 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_accessiblename_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_accessiblename_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_tabindex_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_tabindex_valid.html
index 4c93c7997..b35786a02 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_tabindex_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_tabindex_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_valid.html
index e4e6e49c8..c8b738d47 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_activedescendant_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_application_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_application_label_unique.html
index 02dc458d2..a9c4c3ee3 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_application_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_application_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_application_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_application_labelled.html
index 58abc483b..379b0b19d 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_application_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_application_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_article_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_article_label_unique.html
index 2ba2ed89c..e2823875b 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_article_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_article_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_allowed.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_allowed.html
index 78d2ca33a..4f2764177 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_allowed.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_allowed.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_conflict.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_conflict.html
index 2b88eadea..82aa43ce8 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_conflict.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_conflict.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_deprecated.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_deprecated.html
index 9100544f4..e98801414 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_deprecated.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_deprecated.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_exists.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_exists.html
index 60d5b6a96..555ad6f17 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_redundant.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_redundant.html
index 95620542d..dead9b2c2 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_redundant.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_redundant.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_required.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_required.html
index a6b58e493..b674cf139 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_required.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_required.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_valid.html
index 45b68e844..d93344127 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_attribute_value_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_attribute_value_valid.html
index dcae4746b..fa609a36f 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_attribute_value_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_attribute_value_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_banner_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_banner_label_unique.html
index 0fca3f92f..9330b642b 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_banner_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_banner_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_banner_single.html b/accessibility-checker-engine/help-v4/en-US/aria_banner_single.html
index 4d92daf4b..b70cd8a22 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_banner_single.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_banner_single.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_child_tabbable.html b/accessibility-checker-engine/help-v4/en-US/aria_child_tabbable.html
index 75c31f085..03a17de4a 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_child_tabbable.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_child_tabbable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_child_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_child_valid.html
index 4c7ac2706..db5a5e126 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_child_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_child_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_unique.html
index 363bdea59..756728ddb 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_visible.html b/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_visible.html
index 637e6f344..7ce238541 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_complementary_label_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_complementary_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_complementary_labelled.html
index 18e5a1c60..22b5fcf8c 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_complementary_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_complementary_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_content_in_landmark.html b/accessibility-checker-engine/help-v4/en-US/aria_content_in_landmark.html
index 8d4d43a82..84ca6c455 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_content_in_landmark.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_content_in_landmark.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_label_unique.html
index e310b46d2..93b9568f5 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_misuse.html b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_misuse.html
index cdd842212..63d71a526 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_single.html b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_single.html
index c2da52d8f..b5cb5bedd 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_single.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_contentinfo_single.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_descendant_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_descendant_valid.html
index b17854626..aa037f944 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_descendant_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_descendant_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_document_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_document_label_unique.html
index 9da17bd05..d2bf74476 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_document_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_document_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_eventhandler_role_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_eventhandler_role_valid.html
index dae317b50..20d5dbb25 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_eventhandler_role_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_eventhandler_role_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_form_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_form_label_unique.html
index 708aedb00..b7e08fd4d 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_form_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_form_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_graphic_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_graphic_labelled.html
index 1f4be22b6..4db815aa5 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_graphic_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_graphic_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_hidden_nontabbable.html b/accessibility-checker-engine/help-v4/en-US/aria_hidden_nontabbable.html
index e72359c56..070c4f17d 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_hidden_nontabbable.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_hidden_nontabbable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_id_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_id_unique.html
index 02de60d79..6d1f92a06 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_id_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_id_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_img_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_img_labelled.html
index dda1f5139..482c3b4d1 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_img_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_img_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_keyboard_handler_exists.html b/accessibility-checker-engine/help-v4/en-US/aria_keyboard_handler_exists.html
index 0795186cf..3ea2b2128 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_keyboard_handler_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_keyboard_handler_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_landmark_name_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_landmark_name_unique.html
index f3fa2a98c..bb721e321 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_landmark_name_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_landmark_name_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_main_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_main_label_unique.html
index 114d04b6f..ba9f1c4ea 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_main_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_main_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_main_label_visible.html b/accessibility-checker-engine/help-v4/en-US/aria_main_label_visible.html
index 69f04c92f..27e0137ad 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_main_label_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_main_label_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_navigation_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_navigation_label_unique.html
index 74a4e7b33..03748ad8d 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_navigation_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_navigation_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_parent_required.html b/accessibility-checker-engine/help-v4/en-US/aria_parent_required.html
index e813c660d..8625e7f2c 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_parent_required.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_parent_required.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_region_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_region_label_unique.html
index 316bf2a5f..14e805c4f 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_region_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_region_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_region_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_region_labelled.html
index 3d5a0c89f..91114f0f7 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_region_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_region_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_role_allowed.html b/accessibility-checker-engine/help-v4/en-US/aria_role_allowed.html
index 17fbe3db5..2e45cc4f1 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_role_allowed.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_role_allowed.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_role_redundant.html b/accessibility-checker-engine/help-v4/en-US/aria_role_redundant.html
index 49d711ce6..e4ed4173c 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_role_redundant.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_role_redundant.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_role_valid.html b/accessibility-checker-engine/help-v4/en-US/aria_role_valid.html
index 4ab69e801..504931d66 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_role_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_role_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_search_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_search_label_unique.html
index 2f1961c5a..6709fb942 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_search_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_search_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_toolbar_label_unique.html b/accessibility-checker-engine/help-v4/en-US/aria_toolbar_label_unique.html
index bc397aca0..276b9c13c 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_toolbar_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_toolbar_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/aria_widget_labelled.html b/accessibility-checker-engine/help-v4/en-US/aria_widget_labelled.html
index 004db441c..9227e367c 100644
--- a/accessibility-checker-engine/help-v4/en-US/aria_widget_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/aria_widget_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/asciiart_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/asciiart_alt_exists.html
index 052c48043..50be09a35 100644
--- a/accessibility-checker-engine/help-v4/en-US/asciiart_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/asciiart_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/blink_css_review.html b/accessibility-checker-engine/help-v4/en-US/blink_css_review.html
index 0b4132961..af2145011 100644
--- a/accessibility-checker-engine/help-v4/en-US/blink_css_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/blink_css_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/blink_elem_deprecated.html b/accessibility-checker-engine/help-v4/en-US/blink_elem_deprecated.html
index 8604d4640..39cfa539f 100644
--- a/accessibility-checker-engine/help-v4/en-US/blink_elem_deprecated.html
+++ b/accessibility-checker-engine/help-v4/en-US/blink_elem_deprecated.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/blockquote_cite_exists.html b/accessibility-checker-engine/help-v4/en-US/blockquote_cite_exists.html
index 40668e954..8c09fa506 100644
--- a/accessibility-checker-engine/help-v4/en-US/blockquote_cite_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/blockquote_cite_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/canvas_content_described.html b/accessibility-checker-engine/help-v4/en-US/canvas_content_described.html
index 3f9169d13..6910a93bf 100644
--- a/accessibility-checker-engine/help-v4/en-US/canvas_content_described.html
+++ b/accessibility-checker-engine/help-v4/en-US/canvas_content_described.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/caption_track_exists.html b/accessibility-checker-engine/help-v4/en-US/caption_track_exists.html
index 812ed55b0..5814d66f0 100644
--- a/accessibility-checker-engine/help-v4/en-US/caption_track_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/caption_track_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_active_descendant.html b/accessibility-checker-engine/help-v4/en-US/combobox_active_descendant.html
index 0b8979f4b..c53baedd4 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_active_descendant.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_active_descendant.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_autocomplete_valid.html b/accessibility-checker-engine/help-v4/en-US/combobox_autocomplete_valid.html
index b88ccfe4d..7ed83c085 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_autocomplete_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_autocomplete_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_design_valid.html b/accessibility-checker-engine/help-v4/en-US/combobox_design_valid.html
index 75db1d48a..1083a49c3 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_design_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_design_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_focusable_elements.html b/accessibility-checker-engine/help-v4/en-US/combobox_focusable_elements.html
index d96b302d8..9e8f5c3ad 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_focusable_elements.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_focusable_elements.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_haspopup_valid.html b/accessibility-checker-engine/help-v4/en-US/combobox_haspopup_valid.html
index 9b61a53ee..4ad5c57fd 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_haspopup_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_haspopup_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/combobox_popup_reference.html b/accessibility-checker-engine/help-v4/en-US/combobox_popup_reference.html
index 95f644920..7da80eaac 100644
--- a/accessibility-checker-engine/help-v4/en-US/combobox_popup_reference.html
+++ b/accessibility-checker-engine/help-v4/en-US/combobox_popup_reference.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/dir_attribute_valid.html b/accessibility-checker-engine/help-v4/en-US/dir_attribute_valid.html
index f458ce49f..b8940a050 100644
--- a/accessibility-checker-engine/help-v4/en-US/dir_attribute_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/dir_attribute_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/download_keyboard_controllable.html b/accessibility-checker-engine/help-v4/en-US/download_keyboard_controllable.html
index 68e3535e0..a031acc5d 100644
--- a/accessibility-checker-engine/help-v4/en-US/download_keyboard_controllable.html
+++ b/accessibility-checker-engine/help-v4/en-US/download_keyboard_controllable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_accesskey_labelled.html b/accessibility-checker-engine/help-v4/en-US/element_accesskey_labelled.html
index 3b438e74d..21f308a0c 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_accesskey_labelled.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_accesskey_labelled.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_accesskey_unique.html b/accessibility-checker-engine/help-v4/en-US/element_accesskey_unique.html
index bed631d69..407f4a426 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_accesskey_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_accesskey_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_attribute_deprecated.html b/accessibility-checker-engine/help-v4/en-US/element_attribute_deprecated.html
index 1fe3482bd..373ef6114 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_attribute_deprecated.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_attribute_deprecated.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_id_unique.html b/accessibility-checker-engine/help-v4/en-US/element_id_unique.html
index a179af07e..920642958 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_id_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_id_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_lang_valid.html b/accessibility-checker-engine/help-v4/en-US/element_lang_valid.html
index bc6bf69ba..ab70f95c8 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_lang_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_lang_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_mouseevent_keyboard.html b/accessibility-checker-engine/help-v4/en-US/element_mouseevent_keyboard.html
index e1b33feb3..104a553d3 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_mouseevent_keyboard.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_mouseevent_keyboard.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_orientation_unlocked.html b/accessibility-checker-engine/help-v4/en-US/element_orientation_unlocked.html
index 7aacc5679..cad95322b 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_orientation_unlocked.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_orientation_unlocked.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_scrollable_tabbable.html b/accessibility-checker-engine/help-v4/en-US/element_scrollable_tabbable.html
index ad4d3f422..e4be1b9d4 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_scrollable_tabbable.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_scrollable_tabbable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_tabbable_role_valid.html b/accessibility-checker-engine/help-v4/en-US/element_tabbable_role_valid.html
index ff771f967..26221577a 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_tabbable_role_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_tabbable_role_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_tabbable_unobscured.html b/accessibility-checker-engine/help-v4/en-US/element_tabbable_unobscured.html
index 870cd8dd7..fa9d44e73 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_tabbable_unobscured.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_tabbable_unobscured.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/element_tabbable_visible.html b/accessibility-checker-engine/help-v4/en-US/element_tabbable_visible.html
index d4d749dc6..3b0f33605 100644
--- a/accessibility-checker-engine/help-v4/en-US/element_tabbable_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/element_tabbable_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/embed_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/embed_alt_exists.html
index 956460a5d..115a2e69b 100644
--- a/accessibility-checker-engine/help-v4/en-US/embed_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/embed_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/embed_noembed_exists.html b/accessibility-checker-engine/help-v4/en-US/embed_noembed_exists.html
index 1ec03c389..268b3bf7a 100644
--- a/accessibility-checker-engine/help-v4/en-US/embed_noembed_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/embed_noembed_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/emoticons_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/emoticons_alt_exists.html
index 490c45aae..06af242c7 100644
--- a/accessibility-checker-engine/help-v4/en-US/emoticons_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/emoticons_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/error_message_exists.html b/accessibility-checker-engine/help-v4/en-US/error_message_exists.html
index 576f51fae..d6ea6298c 100644
--- a/accessibility-checker-engine/help-v4/en-US/error_message_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/error_message_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/fieldset_label_valid.html b/accessibility-checker-engine/help-v4/en-US/fieldset_label_valid.html
index ded54f9c8..909f81e5d 100644
--- a/accessibility-checker-engine/help-v4/en-US/fieldset_label_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/fieldset_label_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/fieldset_legend_valid.html b/accessibility-checker-engine/help-v4/en-US/fieldset_legend_valid.html
index 6564b8798..8847c4d62 100644
--- a/accessibility-checker-engine/help-v4/en-US/fieldset_legend_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/fieldset_legend_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/figure_label_exists.html b/accessibility-checker-engine/help-v4/en-US/figure_label_exists.html
index 77b853d27..83ff51005 100644
--- a/accessibility-checker-engine/help-v4/en-US/figure_label_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/figure_label_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/form_font_color.html b/accessibility-checker-engine/help-v4/en-US/form_font_color.html
index d22346ff9..7e8e3f5d2 100644
--- a/accessibility-checker-engine/help-v4/en-US/form_font_color.html
+++ b/accessibility-checker-engine/help-v4/en-US/form_font_color.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/form_interaction_review.html b/accessibility-checker-engine/help-v4/en-US/form_interaction_review.html
index aff0b5d41..02d3e9e7c 100644
--- a/accessibility-checker-engine/help-v4/en-US/form_interaction_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/form_interaction_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/form_label_unique.html b/accessibility-checker-engine/help-v4/en-US/form_label_unique.html
index 0e0f39012..8ef1af8d6 100644
--- a/accessibility-checker-engine/help-v4/en-US/form_label_unique.html
+++ b/accessibility-checker-engine/help-v4/en-US/form_label_unique.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/form_submit_button_exists.html b/accessibility-checker-engine/help-v4/en-US/form_submit_button_exists.html
index a6bd090a2..44dd0b354 100644
--- a/accessibility-checker-engine/help-v4/en-US/form_submit_button_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/form_submit_button_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/form_submit_review.html b/accessibility-checker-engine/help-v4/en-US/form_submit_review.html
index d7eac04d5..a4536fbc7 100644
--- a/accessibility-checker-engine/help-v4/en-US/form_submit_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/form_submit_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/frame_src_valid.html b/accessibility-checker-engine/help-v4/en-US/frame_src_valid.html
index 79d47f0ac..46c601f10 100644
--- a/accessibility-checker-engine/help-v4/en-US/frame_src_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/frame_src_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/frame_title_exists.html b/accessibility-checker-engine/help-v4/en-US/frame_title_exists.html
index f685b4c72..776fec988 100644
--- a/accessibility-checker-engine/help-v4/en-US/frame_title_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/frame_title_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/heading_content_exists.html b/accessibility-checker-engine/help-v4/en-US/heading_content_exists.html
index 87b7abfde..5e951ff68 100644
--- a/accessibility-checker-engine/help-v4/en-US/heading_content_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/heading_content_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/heading_markup_misuse.html b/accessibility-checker-engine/help-v4/en-US/heading_markup_misuse.html
index 5f02b10d7..5cdf1ebd4 100644
--- a/accessibility-checker-engine/help-v4/en-US/heading_markup_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/heading_markup_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/html_lang_exists.html b/accessibility-checker-engine/help-v4/en-US/html_lang_exists.html
index e990f164f..cd2471fa8 100644
--- a/accessibility-checker-engine/help-v4/en-US/html_lang_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/html_lang_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/html_lang_valid.html b/accessibility-checker-engine/help-v4/en-US/html_lang_valid.html
index a8ff606ca..21482867d 100644
--- a/accessibility-checker-engine/help-v4/en-US/html_lang_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/html_lang_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/html_skipnav_exists.html b/accessibility-checker-engine/help-v4/en-US/html_skipnav_exists.html
index 6a1acac46..39275d858 100644
--- a/accessibility-checker-engine/help-v4/en-US/html_skipnav_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/html_skipnav_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/iframe_interactive_tabbable.html b/accessibility-checker-engine/help-v4/en-US/iframe_interactive_tabbable.html
index fff72f037..cbd291c98 100644
--- a/accessibility-checker-engine/help-v4/en-US/iframe_interactive_tabbable.html
+++ b/accessibility-checker-engine/help-v4/en-US/iframe_interactive_tabbable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/imagebutton_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/imagebutton_alt_exists.html
index b704c2d3f..2ea6ce7d3 100644
--- a/accessibility-checker-engine/help-v4/en-US/imagebutton_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/imagebutton_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/imagemap_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/imagemap_alt_exists.html
index 78a3ab8e2..3779534a2 100644
--- a/accessibility-checker-engine/help-v4/en-US/imagemap_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/imagemap_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_background.html b/accessibility-checker-engine/help-v4/en-US/img_alt_background.html
index 0c78b5682..8aabaddb6 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_background.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_background.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_decorative.html b/accessibility-checker-engine/help-v4/en-US/img_alt_decorative.html
index c95473844..f7c215ea7 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_decorative.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_decorative.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_misuse.html b/accessibility-checker-engine/help-v4/en-US/img_alt_misuse.html
index ea322be7c..9e61bac9c 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_null.html b/accessibility-checker-engine/help-v4/en-US/img_alt_null.html
index 84d32c775..48273c850 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_null.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_null.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_redundant.html b/accessibility-checker-engine/help-v4/en-US/img_alt_redundant.html
index 049b15685..ce4b52d8a 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_redundant.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_redundant.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_alt_valid.html b/accessibility-checker-engine/help-v4/en-US/img_alt_valid.html
index 51e2e6b1c..4fdb48382 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_alt_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_alt_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_ismap_misuse.html b/accessibility-checker-engine/help-v4/en-US/img_ismap_misuse.html
index a88d58ef6..8c780ecfa 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_ismap_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_ismap_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/img_longdesc_misuse.html b/accessibility-checker-engine/help-v4/en-US/img_longdesc_misuse.html
index 3104e8e4b..f87a21630 100644
--- a/accessibility-checker-engine/help-v4/en-US/img_longdesc_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/img_longdesc_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_autocomplete_valid.html b/accessibility-checker-engine/help-v4/en-US/input_autocomplete_valid.html
index 0256fe979..e5cebbada 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_autocomplete_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_autocomplete_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_checkboxes_grouped.html b/accessibility-checker-engine/help-v4/en-US/input_checkboxes_grouped.html
index 0a806be90..fe67f4b28 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_checkboxes_grouped.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_checkboxes_grouped.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_fields_grouped.html b/accessibility-checker-engine/help-v4/en-US/input_fields_grouped.html
index 7ca30859d..b05f36fe8 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_fields_grouped.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_fields_grouped.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_haspopup_conflict.html b/accessibility-checker-engine/help-v4/en-US/input_haspopup_conflict.html
index fd11d1c0b..a2cefd0e7 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_haspopup_conflict.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_haspopup_conflict.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_label_after.html b/accessibility-checker-engine/help-v4/en-US/input_label_after.html
index 58849df65..2243bbcf8 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_label_after.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_label_after.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_label_before.html b/accessibility-checker-engine/help-v4/en-US/input_label_before.html
index c749781a4..3b2aab172 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_label_before.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_label_before.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_label_exists.html b/accessibility-checker-engine/help-v4/en-US/input_label_exists.html
index 10a90af4c..a24968ea1 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_label_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_label_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_label_visible.html b/accessibility-checker-engine/help-v4/en-US/input_label_visible.html
index 16bfe6ac0..b9238016d 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_label_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_label_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_onchange_review.html b/accessibility-checker-engine/help-v4/en-US/input_onchange_review.html
index 9d7c968e5..476d698c0 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_onchange_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_onchange_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/input_placeholder_label_visible.html b/accessibility-checker-engine/help-v4/en-US/input_placeholder_label_visible.html
index 9ee594d37..48d02048d 100644
--- a/accessibility-checker-engine/help-v4/en-US/input_placeholder_label_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/input_placeholder_label_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/label_content_exists.html b/accessibility-checker-engine/help-v4/en-US/label_content_exists.html
index ee6f54047..1a3f8eb14 100644
--- a/accessibility-checker-engine/help-v4/en-US/label_content_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/label_content_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/label_name_visible.html b/accessibility-checker-engine/help-v4/en-US/label_name_visible.html
index d9af89b11..11ecc8b80 100644
--- a/accessibility-checker-engine/help-v4/en-US/label_name_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/label_name_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/label_ref_valid.html b/accessibility-checker-engine/help-v4/en-US/label_ref_valid.html
index e588459b6..79aba84fb 100644
--- a/accessibility-checker-engine/help-v4/en-US/label_ref_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/label_ref_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/list_children_valid.html b/accessibility-checker-engine/help-v4/en-US/list_children_valid.html
index 3bbd2d6f6..a2aa09f23 100644
--- a/accessibility-checker-engine/help-v4/en-US/list_children_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/list_children_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/list_markup_review.html b/accessibility-checker-engine/help-v4/en-US/list_markup_review.html
index 9ac8c40d7..028a218c5 100644
--- a/accessibility-checker-engine/help-v4/en-US/list_markup_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/list_markup_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/list_structure_proper.html b/accessibility-checker-engine/help-v4/en-US/list_structure_proper.html
index c286780cc..f6dabb844 100644
--- a/accessibility-checker-engine/help-v4/en-US/list_structure_proper.html
+++ b/accessibility-checker-engine/help-v4/en-US/list_structure_proper.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/marquee_elem_avoid.html b/accessibility-checker-engine/help-v4/en-US/marquee_elem_avoid.html
index 54c76e51c..014171640 100644
--- a/accessibility-checker-engine/help-v4/en-US/marquee_elem_avoid.html
+++ b/accessibility-checker-engine/help-v4/en-US/marquee_elem_avoid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_alt_brief.html b/accessibility-checker-engine/help-v4/en-US/media_alt_brief.html
index 23a7591d4..6a0bb4cba 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_alt_brief.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_alt_brief.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_alt_exists.html b/accessibility-checker-engine/help-v4/en-US/media_alt_exists.html
index ed4ead7b6..99f40b95a 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_alt_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_alt_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_audio_transcribed.html b/accessibility-checker-engine/help-v4/en-US/media_audio_transcribed.html
index 1a25a34e6..4f0a5130f 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_audio_transcribed.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_audio_transcribed.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_autostart_controllable.html b/accessibility-checker-engine/help-v4/en-US/media_autostart_controllable.html
index 21368759a..55fbeabe9 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_autostart_controllable.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_autostart_controllable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_keyboard_controllable.html b/accessibility-checker-engine/help-v4/en-US/media_keyboard_controllable.html
index 1e3734d44..381fd907e 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_keyboard_controllable.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_keyboard_controllable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_live_captioned.html b/accessibility-checker-engine/help-v4/en-US/media_live_captioned.html
index bfacb1e87..9cb388e0e 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_live_captioned.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_live_captioned.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/media_track_available.html b/accessibility-checker-engine/help-v4/en-US/media_track_available.html
index 30cf5faab..f7e54e65a 100644
--- a/accessibility-checker-engine/help-v4/en-US/media_track_available.html
+++ b/accessibility-checker-engine/help-v4/en-US/media_track_available.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/meta_redirect_optional.html b/accessibility-checker-engine/help-v4/en-US/meta_redirect_optional.html
index de5d0e9c6..f1e84b714 100644
--- a/accessibility-checker-engine/help-v4/en-US/meta_redirect_optional.html
+++ b/accessibility-checker-engine/help-v4/en-US/meta_redirect_optional.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/meta_refresh_delay.html b/accessibility-checker-engine/help-v4/en-US/meta_refresh_delay.html
index 61aaf4381..62367d72c 100644
--- a/accessibility-checker-engine/help-v4/en-US/meta_refresh_delay.html
+++ b/accessibility-checker-engine/help-v4/en-US/meta_refresh_delay.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/meta_viewport_zoomable.html b/accessibility-checker-engine/help-v4/en-US/meta_viewport_zoomable.html
index e40022f37..145acd997 100644
--- a/accessibility-checker-engine/help-v4/en-US/meta_viewport_zoomable.html
+++ b/accessibility-checker-engine/help-v4/en-US/meta_viewport_zoomable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/noembed_content_exists.html b/accessibility-checker-engine/help-v4/en-US/noembed_content_exists.html
index 44b903809..4eb68c67d 100644
--- a/accessibility-checker-engine/help-v4/en-US/noembed_content_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/noembed_content_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/object_text_exists.html b/accessibility-checker-engine/help-v4/en-US/object_text_exists.html
index 1070775b0..4f8c88c1c 100644
--- a/accessibility-checker-engine/help-v4/en-US/object_text_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/object_text_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/page_title_exists.html b/accessibility-checker-engine/help-v4/en-US/page_title_exists.html
index c18a11078..76b5ab50d 100644
--- a/accessibility-checker-engine/help-v4/en-US/page_title_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/page_title_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/page_title_valid.html b/accessibility-checker-engine/help-v4/en-US/page_title_valid.html
index fd340381a..2cb259287 100644
--- a/accessibility-checker-engine/help-v4/en-US/page_title_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/page_title_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/script_focus_blur_review.html b/accessibility-checker-engine/help-v4/en-US/script_focus_blur_review.html
index d86fe62b4..a8b0e6af2 100644
--- a/accessibility-checker-engine/help-v4/en-US/script_focus_blur_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/script_focus_blur_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/script_onclick_avoid.html b/accessibility-checker-engine/help-v4/en-US/script_onclick_avoid.html
index 5c2a2888e..8d4c8468b 100644
--- a/accessibility-checker-engine/help-v4/en-US/script_onclick_avoid.html
+++ b/accessibility-checker-engine/help-v4/en-US/script_onclick_avoid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/script_onclick_misuse.html b/accessibility-checker-engine/help-v4/en-US/script_onclick_misuse.html
index 3a8b516f4..56187d47d 100644
--- a/accessibility-checker-engine/help-v4/en-US/script_onclick_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/script_onclick_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/script_select_review.html b/accessibility-checker-engine/help-v4/en-US/script_select_review.html
index dafbdc9ec..921e865d3 100644
--- a/accessibility-checker-engine/help-v4/en-US/script_select_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/script_select_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/select_options_grouped.html b/accessibility-checker-engine/help-v4/en-US/select_options_grouped.html
index 53cecc494..1834183d3 100644
--- a/accessibility-checker-engine/help-v4/en-US/select_options_grouped.html
+++ b/accessibility-checker-engine/help-v4/en-US/select_options_grouped.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/skip_main_described.html b/accessibility-checker-engine/help-v4/en-US/skip_main_described.html
index 0b44abc54..86c35c382 100644
--- a/accessibility-checker-engine/help-v4/en-US/skip_main_described.html
+++ b/accessibility-checker-engine/help-v4/en-US/skip_main_described.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/skip_main_exists.html b/accessibility-checker-engine/help-v4/en-US/skip_main_exists.html
index 5a87fd00b..26d597d38 100644
--- a/accessibility-checker-engine/help-v4/en-US/skip_main_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/skip_main_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_background_decorative.html b/accessibility-checker-engine/help-v4/en-US/style_background_decorative.html
index b461d483a..e42e8fa0d 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_background_decorative.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_background_decorative.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_before_after_review.html b/accessibility-checker-engine/help-v4/en-US/style_before_after_review.html
index 217f4c5c2..b3066377c 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_before_after_review.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_before_after_review.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_color_misuse.html b/accessibility-checker-engine/help-v4/en-US/style_color_misuse.html
index 5a586bc2c..5474667b6 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_color_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_color_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_focus_visible.html b/accessibility-checker-engine/help-v4/en-US/style_focus_visible.html
index 64229b01a..8ff590ef7 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_focus_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_focus_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_highcontrast_visible.html b/accessibility-checker-engine/help-v4/en-US/style_highcontrast_visible.html
index 4e3eea989..704639104 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_highcontrast_visible.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_highcontrast_visible.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/style_hover_persistent.html b/accessibility-checker-engine/help-v4/en-US/style_hover_persistent.html
index a1b77eacd..c86bf7140 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_hover_persistent.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_hover_persistent.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
@@ -62,6 +63,7 @@ <h3 id="ruleMessage"></h3>
 The recommended code example is:
 
 ```
+<!DOCTYPE html>
 <html lang="en-US">
   <head>
     <style>
diff --git a/accessibility-checker-engine/help-v4/en-US/style_viewport_resizable.html b/accessibility-checker-engine/help-v4/en-US/style_viewport_resizable.html
index fef0ab34b..b04a10c18 100644
--- a/accessibility-checker-engine/help-v4/en-US/style_viewport_resizable.html
+++ b/accessibility-checker-engine/help-v4/en-US/style_viewport_resizable.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_aria_descendants.html b/accessibility-checker-engine/help-v4/en-US/table_aria_descendants.html
index a8efa0cb7..ad1f16e44 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_aria_descendants.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_aria_descendants.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_caption_empty.html b/accessibility-checker-engine/help-v4/en-US/table_caption_empty.html
index c28c804d2..1ce73c387 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_caption_empty.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_caption_empty.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_caption_nested.html b/accessibility-checker-engine/help-v4/en-US/table_caption_nested.html
index eed542f55..d42de5ab6 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_caption_nested.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_caption_nested.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_headers_exists.html b/accessibility-checker-engine/help-v4/en-US/table_headers_exists.html
index 6b4407ff6..2680908d4 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_headers_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_headers_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_headers_ref_valid.html b/accessibility-checker-engine/help-v4/en-US/table_headers_ref_valid.html
index 2287f0b56..2895f169c 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_headers_ref_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_headers_ref_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_headers_related.html b/accessibility-checker-engine/help-v4/en-US/table_headers_related.html
index 97cc8181f..304b8c417 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_headers_related.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_headers_related.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_layout_linearized.html b/accessibility-checker-engine/help-v4/en-US/table_layout_linearized.html
index 388d470f3..f2e826a53 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_layout_linearized.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_layout_linearized.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_scope_valid.html b/accessibility-checker-engine/help-v4/en-US/table_scope_valid.html
index dd64b1908..c68c1b121 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_scope_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_scope_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_structure_misuse.html b/accessibility-checker-engine/help-v4/en-US/table_structure_misuse.html
index dd580c5e7..d5eda0950 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_structure_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_structure_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/table_summary_redundant.html b/accessibility-checker-engine/help-v4/en-US/table_summary_redundant.html
index c02d81885..a27efc4ae 100644
--- a/accessibility-checker-engine/help-v4/en-US/table_summary_redundant.html
+++ b/accessibility-checker-engine/help-v4/en-US/table_summary_redundant.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_block_heading.html b/accessibility-checker-engine/help-v4/en-US/text_block_heading.html
index 4e31dfd18..531654ccf 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_block_heading.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_block_heading.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_contrast_sufficient.html b/accessibility-checker-engine/help-v4/en-US/text_contrast_sufficient.html
index 927bc071f..f6587ff57 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_contrast_sufficient.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_contrast_sufficient.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_quoted_correctly.html b/accessibility-checker-engine/help-v4/en-US/text_quoted_correctly.html
index 4aadac644..7c87d8726 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_quoted_correctly.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_quoted_correctly.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_sensory_misuse.html b/accessibility-checker-engine/help-v4/en-US/text_sensory_misuse.html
index af23bd734..e05525a76 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_sensory_misuse.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_sensory_misuse.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_spacing_valid.html b/accessibility-checker-engine/help-v4/en-US/text_spacing_valid.html
index 6b75ebb79..1a80a9005 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_spacing_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_spacing_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/text_whitespace_valid.html b/accessibility-checker-engine/help-v4/en-US/text_whitespace_valid.html
index 10964a89b..c5e092530 100644
--- a/accessibility-checker-engine/help-v4/en-US/text_whitespace_valid.html
+++ b/accessibility-checker-engine/help-v4/en-US/text_whitespace_valid.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/widget_tabbable_exists.html b/accessibility-checker-engine/help-v4/en-US/widget_tabbable_exists.html
index c22577841..9aa55e10c 100644
--- a/accessibility-checker-engine/help-v4/en-US/widget_tabbable_exists.html
+++ b/accessibility-checker-engine/help-v4/en-US/widget_tabbable_exists.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--
diff --git a/accessibility-checker-engine/help-v4/en-US/widget_tabbable_single.html b/accessibility-checker-engine/help-v4/en-US/widget_tabbable_single.html
index fde900d60..f4f86b2d4 100644
--- a/accessibility-checker-engine/help-v4/en-US/widget_tabbable_single.html
+++ b/accessibility-checker-engine/help-v4/en-US/widget_tabbable_single.html
@@ -1,3 +1,4 @@
+<!DOCTYPE html>
 <html lang="en-US">
 <head>
     <!--