$ git clone -n https://src.fedoraproject.org/rpms/ghc-tar.git /var/lib/mock/f38-build-side-42-init-devel-951682-28780/root/chroot_tmpdir/scmroot/ghc-tar
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-951682-28780/root/chroot_tmpdir/scmroot/ghc-tar'...
$ git fetch origin fe0a7151a68667933c158032f8f8190fa0635f85:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-tar
 * [new ref]         fe0a7151a68667933c158032f8f8190fa0635f85 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe0a715 Convert to %autorelease and %autochangelog