$ git clone -n https://src.fedoraproject.org/forks/hypersa/rpms/ghc-concurrent-output.git /var/lib/mock/f39-build-2227260-53002/root/chroot_tmpdir/scmroot/ghc-concurrent-output
Cloning into '/var/lib/mock/f39-build-2227260-53002/root/chroot_tmpdir/scmroot/ghc-concurrent-output'...
$ git fetch origin 2cbf7600a81c87f451fce01f0d5df6a257e0fd61:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/forks/hypersa/rpms/ghc-concurrent-output
 * [new ref]         2cbf7600a81c87f451fce01f0d5df6a257e0fd61 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2cbf760 rv64 rebuild