/usr/share/aide/config/aide/aide.conf.d/31_aide_mdadm 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 | /@@{RUN}/mdadm/(monitor|autorebuild)\.pid$ VarFile
/run/mdadm/m(ap|d[0-9]+-uevent)$ VarInode
/@@{RUN}/mdadm$ VarDirInode
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