$ git clone -n https://src.fedoraproject.org/rpms/stgit.git /var/lib/mock/f40-build-1552909-23943/root/chroot_tmpdir/scmroot/stgit
Cloning into '/var/lib/mock/f40-build-1552909-23943/root/chroot_tmpdir/scmroot/stgit'...
$ git fetch origin 8c52838596fe52d51b4a5998a913a7a3aad68dc7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/stgit
 * [new ref]         8c52838596fe52d51b4a5998a913a7a3aad68dc7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8c52838 Update gix dependency to 0.63