;;;###autoload
(define-derived-mode diff-mode fundamental-mode "Diff"
"Major mode for viewing/editing context diffs.
-Supports unified and context diffs as well as (to a lesser extent)
-normal diffs.
+Supports unified and context diffs as well as, to a lesser extent, diffs
+in the old \"normal\" format. (Unified diffs have become the standard,
+most commonly encountered format.)
When the buffer is read-only, the ESC prefix is not necessary.
If you edit the buffer manually, `diff-mode' will try to update the hunk