$ git clone -n https://src.fedoraproject.org/rpms/mame.git /var/lib/mock/f39-build-1641999-40211/root/chroot_tmpdir/scmroot/mame
Cloning into '/var/lib/mock/f39-build-1641999-40211/root/chroot_tmpdir/scmroot/mame'...
$ git fetch origin 1624b1c617e63605b5a9c12a199fc4eb7263e0b4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mame
 * [new ref]         1624b1c617e63605b5a9c12a199fc4eb7263e0b4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1624b1c Enable wayland support