$ git clone -n https://src.fedoraproject.org/rpms/xcircuit.git /var/lib/mock/f42-build-868821-176267/root/chroot_tmpdir/scmroot/xcircuit
Cloning into '/var/lib/mock/f42-build-868821-176267/root/chroot_tmpdir/scmroot/xcircuit'...
$ git fetch origin a293d4d21e23d17c5d1b211e6564b8656b7d921d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xcircuit
 * [new ref]         a293d4d21e23d17c5d1b211e6564b8656b7d921d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a293d4d Use tk8 explicitly