$ git clone -n https://src.fedoraproject.org/rpms/ghc-Only.git /var/lib/mock/f38-build-side-42-init-devel-604947-26244/root/chroot_tmpdir/scmroot/ghc-Only
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-604947-26244/root/chroot_tmpdir/scmroot/ghc-Only'...
$ git fetch origin ce2c1291fba1ef80fd5cb6ab27c7f4b4cd37d0de:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-Only
 * [new ref]         ce2c1291fba1ef80fd5cb6ab27c7f4b4cd37d0de -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ce2c129 Convert to %autorelease and %autochangelog