$ git clone -n https://src.fedoraproject.org/rpms/rccl.git /var/lib/mock/f42-build-3530700-46321/root/chroot_tmpdir/scmroot/rccl
Cloning into '/var/lib/mock/f42-build-3530700-46321/root/chroot_tmpdir/scmroot/rccl'...
$ git fetch origin b9e129b7669761930a8ed291e69f5b0a4c1297d3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rccl
 * [new ref]         b9e129b7669761930a8ed291e69f5b0a4c1297d3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b9e129b Fix suse