@Override
	protected Object getUnresolvedReferenceValue(String primaryId, String unresolvedId) {
		Msg.warn(this,
			"Could not resolve indirect property for \"" + unresolvedId +
				"\" for primary id \"" + primaryId + "\", using last resort default");
		return false;
	}
A Java property value for keys that use boolean values.
Ghidra/Framework/Gui/src/main/java/generic/theme/BooleanPropertyValue.java