$ git clone -n https://src.fedoraproject.org/rpms/ghc-rfc5051.git /var/lib/mock/f41-build-837785-159384/root/chroot_tmpdir/scmroot/ghc-rfc5051
Cloning into '/var/lib/mock/f41-build-837785-159384/root/chroot_tmpdir/scmroot/ghc-rfc5051'...
$ git fetch origin acd0d0155ce5fdf2dcc66b27baebfaeaaf254ada:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-rfc5051
 * [new ref]         acd0d0155ce5fdf2dcc66b27baebfaeaaf254ada -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at acd0d01 bump release