diff --git a/README.md b/README.md
index 4846ac2..6aec2a2 100644
--- a/README.md
+++ b/README.md
@@ -220,7 +220,7 @@ please note, this step is only needed when arch is to be installed on a new host
   - [OBSOLETE | option settings should be synced]
     - update singlefile
       - name format (extension icon ➔ manage extensions ➔ extensions ➔ singlefile ➔ preferences ➔ file format):
-        - new: `{year-locale}{month-locale}{day-locale}_{hours-locale}{minutes-locale}_{url-hostname-subdomains}{url-hostname-domain}{url-hostname-suffix}{url-pathname-flat}`
+        - new: `{year-locale}{month-locale}{day-locale}_{hours-locale}{minutes-locale}_{url-hostname-subdomains}{url-hostname-domain}{url-hostname-suffix}{url-pathname-flat}.{filename-extension}`
       - open "save as" dialog (… ➔ file format):
         - check 'open the "Save as" dialog to confirm the file name'
   - sidebery ➔ settings ➔