diff --git a/filetypes.xml b/filetypes.xml
index f60d5ab..b748594 100644
--- a/filetypes.xml
+++ b/filetypes.xml
@@ -10,6 +10,7 @@
       <mapping ext="opf" type="PLAIN_TEXT" />
       <mapping ext="properties" type="PLAIN_TEXT" />
       <mapping ext="old" type="PLAIN_TEXT" />
+      <mapping ext="hml" type="XHTML" />
     </extensionMap>
   </component>
 </application>
\ No newline at end of file