$ git clone -n https://src.fedoraproject.org/rpms/manifest-tool.git /var/lib/mock/f38-build-side-42-init-devel-1137377-30386/root/chroot_tmpdir/scmroot/manifest-tool
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1137377-30386/root/chroot_tmpdir/scmroot/manifest-tool'...
$ git fetch origin e6c4aaefe9820021329d7e780830548ef249474a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/manifest-tool
 * [new ref]         e6c4aaefe9820021329d7e780830548ef249474a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e6c4aae Update to latest upstream release