$ git clone -n https://src.fedoraproject.org/rpms/free42.git /var/lib/mock/f39-build-1587388-38222/root/chroot_tmpdir/scmroot/free42
Cloning into '/var/lib/mock/f39-build-1587388-38222/root/chroot_tmpdir/scmroot/free42'...
$ git fetch origin 417e22e6b3d5f081724f1a0c92b62d6cd76d3cfe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/free42
 * [new ref]         417e22e6b3d5f081724f1a0c92b62d6cd76d3cfe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 417e22e Update to 3.0.21