This is Debian GNU/Linux's prepackaged version of the 'xlock' utility.
'xlock' locks the X server until the user enters his/her password at the 
keyboard. 'xlock' was originally written by Patrick J. Naughton, the 
'xlockmore' extended version is written and maintained by David A. Bagley.
Various modes have been contributed by other programmers.

The current debian package maintainer is Michael Stone <mstone@debian.org> and
is based on the version of xlockmore available at
ftp://ftp.tux.org/pub/people/david-bagley/xlockmore/xlockmore-5.13.tar.bz2
This debian package was originally compiled by Dirk Eddc                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     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