$ git clone -n https://src.fedoraproject.org/rpms/RBTools.git /var/lib/mock/f41-build-side-1-2810937-32924/root/chroot_tmpdir/scmroot/RBTools
Cloning into '/var/lib/mock/f41-build-side-1-2810937-32924/root/chroot_tmpdir/scmroot/RBTools'...
$ git fetch origin b9133d537868243e05b758445fe447bd8a8de931:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/RBTools
 * [new ref]         b9133d537868243e05b758445fe447bd8a8de931 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b9133d5 Update to 5.0 (rhbz#2290688)