This module is a filter for SVN::Notify that translates user account
names (e.g. "user1") into email addresses. It does this based on a
colon-separated file, like a UNIX passwd file (or more usefully)
the AuthUserFile used by Apache. The file path is specified via the
--account_file option to the svnnotify script, and the index
(zero-based) of the email field is specified via the --account_field
option.

WWW: https://metacpan.org/release/SVN-Notify-Filter-EmailFlatFileDB