diff --git a/.github/workflows/deploy-demo.yml b/.github/workflows/deploy-demo.yml
index a99880f..5b40f13 100644
--- a/.github/workflows/deploy-demo.yml
+++ b/.github/workflows/deploy-demo.yml
@@ -108,7 +108,6 @@ jobs:
             -m demo-metadata.json \
             --service github-to-sqlite \
             --branch=main \
-            --install=py-gfm \
             --install=datasette-search-all>=0.3 \
             --install=datasette-render-markdown>=1.1.2 \
             --install=datasette-pretty-json \
diff --git a/demo-metadata.json b/demo-metadata.json
index 293c947..c04aa5a 100644
--- a/demo-metadata.json
+++ b/demo-metadata.json
@@ -45,10 +45,7 @@
                                 "span": [
                                     "class"
                                 ]
-                            },
-                            "extensions": [
-                                "mdx_gfm:GithubFlavoredMarkdownExtension"
-                            ]
+                            }
                         }
                     }
                 },
@@ -89,10 +86,7 @@
                                 "span": [
                                     "class"
                                 ]
-                            },
-                            "extensions": [
-                                "mdx_gfm:GithubFlavoredMarkdownExtension"
-                            ]
+                            }
                         }
                     }
                 },
@@ -138,10 +132,7 @@
                                 "span": [
                                     "class"
                                 ]
-                            },
-                            "extensions": [
-                                "mdx_gfm:GithubFlavoredMarkdownExtension"
-                            ]
+                            }
                         }
                     }
                 },
@@ -180,10 +171,7 @@
                                 "span": [
                                     "class"
                                 ]
-                            },
-                            "extensions": [
-                                "mdx_gfm:GithubFlavoredMarkdownExtension"
-                            ]
+                            }
                         }
                     }
                 }