$ git clone -n https://src.fedoraproject.org/rpms/vdr.git /var/lib/mock/f40-build-1898227-25068/root/chroot_tmpdir/scmroot/vdr
Cloning into '/var/lib/mock/f40-build-1898227-25068/root/chroot_tmpdir/scmroot/vdr'...
$ git fetch origin 3431721d64ec4a1fe38a42d87393fbbd5c3ade3d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vdr
 * [new ref]         3431721d64ec4a1fe38a42d87393fbbd5c3ade3d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3431721 Update to 2.6.9