--- a/doc/hgrc.5.txt
+++ b/doc/hgrc.5.txt
@@ -439,6 +439,9 @@ ui::
The committer of a changeset created when running "commit".
Typically a person's name and email address, e.g. "Fred Widget
<fred@example.com>". Default is $EMAIL or username@hostname.
+ If the username in hgrc is empty, it has to be specified manually or
+ in a different hgrc file (e.g. $HOME/.hgrc, if the admin set "username ="
+ in the system hgrc).
verbose;;
Increase the amount of output printed. True or False. Default is False.