$ git clone -n https://src.fedoraproject.org/rpms/mail-notification.git /var/lib/mock/f40-build-2220165-52654/root/chroot_tmpdir/scmroot/mail-notification
Cloning into '/var/lib/mock/f40-build-2220165-52654/root/chroot_tmpdir/scmroot/mail-notification'...
$ git fetch origin f91a6635e330d7336c6632806a960fa8e03e548a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mail-notification
 * [new ref]         f91a6635e330d7336c6632806a960fa8e03e548a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f91a663 Add patch to adapt to libxml2 changes