$ git clone -n https://src.fedoraproject.org/rpms/thunderbird.git /var/lib/mock/f40-build-796752-140845/root/chroot_tmpdir/scmroot/thunderbird
Cloning into '/var/lib/mock/f40-build-796752-140845/root/chroot_tmpdir/scmroot/thunderbird'...
$ git fetch origin 3f5acef3acda04828951e43a8aba3aab5a6d3727:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/thunderbird
 * [new ref]         3f5acef3acda04828951e43a8aba3aab5a6d3727 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f5acef Update to 115.8.1