$ git clone -n https://src.fedoraproject.org/rpms/xorg-x11-xtrans-devel.git /var/lib/mock/f41-build-side-1-3135088-39766/root/chroot_tmpdir/scmroot/xorg-x11-xtrans-devel
Cloning into '/var/lib/mock/f41-build-side-1-3135088-39766/root/chroot_tmpdir/scmroot/xorg-x11-xtrans-devel'...
$ git fetch origin b3a01da2eb475e65dd52c10be3874e7254bbf11c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xorg-x11-xtrans-devel
 * [new ref]         b3a01da2eb475e65dd52c10be3874e7254bbf11c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b3a01da xtrans 1.5.2