$ git clone -n https://src.fedoraproject.org/rpms/R-bench.git /var/lib/mock/f40-build-1944400-25177/root/chroot_tmpdir/scmroot/R-bench
Cloning into '/var/lib/mock/f40-build-1944400-25177/root/chroot_tmpdir/scmroot/R-bench'...
$ git fetch origin 290bab317c8078e888bdb8dc2f4cef65997f0b75:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-bench
 * [new ref]         290bab317c8078e888bdb8dc2f4cef65997f0b75 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 290bab3 R-maint-sig mass rebuild