$ git clone -n https://src.fedoraproject.org/rpms/stgit.git /var/lib/mock/f40-build-800585-143605/root/chroot_tmpdir/scmroot/stgit
Cloning into '/var/lib/mock/f40-build-800585-143605/root/chroot_tmpdir/scmroot/stgit'...
$ git fetch origin d479f59a9412a77d7d4a19f4f5cb873ac06a0e39:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/stgit
 * [new ref]         d479f59a9412a77d7d4a19f4f5cb873ac06a0e39 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d479f59 Update to 2.4.0 (RHBZ#2260849)