$ git clone -n https://src.fedoraproject.org/rpms/python-pygit2.git /var/lib/mock/f39-build-1502897-34948/root/chroot_tmpdir/scmroot/python-pygit2
Cloning into '/var/lib/mock/f39-build-1502897-34948/root/chroot_tmpdir/scmroot/python-pygit2'...
$ git fetch origin b89121496439ff664a5e8f85f1959208f5ab20a0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-pygit2
 * [new ref]         b89121496439ff664a5e8f85f1959208f5ab20a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b891214 Update to 1.13.0 (rhbz#2237912)