/usr/share/aide/config/aide/aide.conf.d/31_aide_xdm is in aide-common 0.16~a2.git20130520-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | !/var/lib/xdm/authdir/authfiles/A:[0-9]-[A-Za-z0-9]{6}$
/var/lib/xdm/authdir/authfiles$ VarDir
/@@{RUN}/xdm\.pid$ VarFile
|