@Override
	public boolean validate(LinkDatabase linkDatabase) {
		if (getTargetAttribute() == null) {
			return true; // no target path to validate
		}

		String ID = linkDatabase.getIDForLink(getTargetAttribute());
		if (ID != null) {
			return true; // valid help ID found
		}
		return false;
	}
A representation of the {@literal <tocdef>} tag, which is a way to define a TOC item entry in 
a TOC_Source.xml file.
Ghidra/Framework/Help/src/main/java/help/validator/model/TOCItemDefinition.java