@Override
	public boolean isExternal() {
		return !id.startsWith(FONT_ID_PREFIX);
	}
Constructor used when the FontValue will inherit its {@link Font} from another FontValue. The
font value field will be null.
@param id the id for this FontValue
@param refId the id of another FontValue that this FontValue will inherit from
Ghidra/Framework/Gui/src/main/java/generic/theme/FontValue.java