private function checkLinkMessage(Tree $tree, $type1, $xref1, $type2, $xref2): string
    {
        /* I18N: The placeholders are GEDCOM XREFs and tags. e.g. “INDI I123 contains a FAMC link to F234.” */
        return I18N::translate(
            '%1$s %2$s has a %3$s link to %4$s.',
            $this->formatType($type1),
            $this->checkLink($tree, $xref1),
            $this->formatType($type2),
            $this->checkLink($tree, $xref2)
        );
    }