public static StringPropertyValue parse(String key, String value) {
		String id = fromExternalId(key);

		if (isStringKey(value)) {
			String refId = fromExternalId(value);
			return new StringPropertyValue(id, refId, null);
		}

		return new StringPropertyValue(id, value);
	}
A Java property value for keys that use String values.
Ghidra/Framework/Gui/src/main/java/generic/theme/StringPropertyValue.java