diff --git a/extensions/html/package.json b/extensions/html/package.json
index 065eb26669b..3e685df1acf 100644
--- a/extensions/html/package.json
+++ b/extensions/html/package.json
@@ -20,6 +20,7 @@
           ".htm",
           ".shtml",
           ".xhtml",
+          ".xhtm",
           ".mdoc",
           ".jsp",
           ".asp",