--- a/hgext/extdiff.py Fri Mar 30 13:39:06 2018 -0700
+++ b/hgext/extdiff.py Fri Mar 30 12:16:46 2018 -0700
@@ -13,6 +13,11 @@
non-option arguments: paths to directories containing snapshots of
files to compare.
+If there is more than one file being compared and the "child" revision
+is the working directory, any modifications made in the external diff
+program will be copied back to the working directory from the temporary
+directory.
+
The extdiff extension also allows you to configure new diff commands, so
you do not need to type :hg:`extdiff -p kdiff3` always. ::