@Override
	public boolean validate(LinkDatabase linkDatabase) {
		TOCItemDefinition definition = linkDatabase.getTOCDefinition(this);
		if (definition != null) {
			return true;
		}

		TOCItemExternal external = linkDatabase.getTOCExternal(this);
		if (external != null) {
			return true;
		}

		return false;
	}
A representation of the {@literal <tocref>} tag, which is a way to reference a TOC item entry in 
a TOC_Source.xml file other than the one in which the reference lives.
Ghidra/Framework/Help/src/main/java/help/validator/model/TOCItemReference.java