$ git clone -n https://src.fedoraproject.org/rpms/urdfdom.git /var/lib/mock/f42-build-863056-171350/root/chroot_tmpdir/scmroot/urdfdom
Cloning into '/var/lib/mock/f42-build-863056-171350/root/chroot_tmpdir/scmroot/urdfdom'...
$ git fetch origin ffdcb5fa3396fcc1cad409ebd78c04c39ba5cd2c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/urdfdom
 * [new ref]         ffdcb5fa3396fcc1cad409ebd78c04c39ba5cd2c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ffdcb5f rebuild for tinyxml2