/var/lib/cobbler/triggers/add/ is in maas-provision-common 2.2.2-0ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/var/lib/cobbler/triggers/add/distro/
/var/lib/cobbler/triggers/add/distro/post/
/var/lib/cobbler/triggers/add/distro/pre/
/var/lib/cobbler/triggers/add/file/
/var/lib/cobbler/triggers/add/file/post/
/var/lib/cobbler/triggers/add/file/pre/
/var/lib/cobbler/triggers/add/mgmtclass/
/var/lib/cobbler/triggers/add/mgmtclass/post/
/var/lib/cobbler/triggers/add/mgmtclass/pre/
/var/lib/cobbler/triggers/add/package/
/var/lib/cobbler/triggers/add/package/post/
/var/lib/cobbler/triggers/add/package/pre/
/var/lib/cobbler/triggers/add/profile/
/var/lib/cobbler/triggers/add/profile/post/
/var/lib/cobbler/triggers/add/profile/pre/
/var/lib/cobbler/triggers/add/repo/
/var/lib/cobbler/triggers/add/repo/post/
/var/lib/cobbler/triggers/add/repo/pre/
/var/lib/cobbler/triggers/add/system/
/var/lib/cobbler/triggers/add/system/post/
/var/lib/cobbler/triggers/add/system/pre/