$ git clone -n https://src.fedoraproject.org/rpms/ghc-rio.git /var/lib/mock/f38-build-side-42-init-devel-1032547-29727/root/chroot_tmpdir/scmroot/ghc-rio
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1032547-29727/root/chroot_tmpdir/scmroot/ghc-rio'...
$ git fetch origin b4db3493d431cce1477ac8eebe8dc490c694948e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-rio
 * [new ref]         b4db3493d431cce1477ac8eebe8dc490c694948e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4db349 Convert to %autorelease and %autochangelog