$ git clone -n https://src.fedoraproject.org/rpms/libcerf.git /var/lib/mock/f42-build-side-1-3505977-45995/root/chroot_tmpdir/scmroot/libcerf
Cloning into '/var/lib/mock/f42-build-side-1-3505977-45995/root/chroot_tmpdir/scmroot/libcerf'...
$ git fetch origin 0140373032c33f99520df88e7c1901e44c01f3cd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libcerf
 * [new ref]         0140373032c33f99520df88e7c1901e44c01f3cd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0140373 Version bump v2.4 (bug #228557)