diff --git a/botocore/httpchecksum.py b/botocore/httpchecksum.py
index 27bea8e248..1dce170e90 100644
--- a/botocore/httpchecksum.py
+++ b/botocore/httpchecksum.py
@@ -298,12 +298,14 @@ def resolve_request_checksum_algorithm(
         return
 
     location_type = "header"
-    if operation_model.has_streaming_input:
+    if (
+        operation_model.has_streaming_input
+        and urlparse(request["url"]).scheme == "https"
+    ):
         # Operations with streaming input must support trailers.
-        if urlparse(request["url"]).scheme == "https":
-            # We only support unsigned trailer checksums currently. As this
-            # disables payload signing we'll only use trailers over TLS.
-            location_type = "trailer"
+        # We only support unsigned trailer checksums currently. As this
+        # disables payload signing we'll only use trailers over TLS.
+        location_type = "trailer"
 
     algorithm = {
         "algorithm": algorithm_name,
diff --git a/botocore/utils.py b/botocore/utils.py
index 73a7e22605..34e1cc4e82 100644
--- a/botocore/utils.py
+++ b/botocore/utils.py
@@ -3255,9 +3255,13 @@ def _is_s3express_request(params):
     return endpoint_properties.get('backend') == 'S3Express'
 
 
-# This is not a public interface and is subject to abrupt breaking changes.
-# Any usage is not advised or supported in external code bases.
 def has_checksum_header(params):
+    """
+    Checks if a header starting with "x-amz-checksum-" is provided in a request.
+
+    This class is considered private and subject to abrupt breaking changes or
+    removal without prior announcement. Please do not use it directly.
+    """
     headers = params['headers']
 
     # If a header matching the x-amz-checksum-* pattern is present, we