public static void initialize() {
		if (INSTANCE instanceof HeadlessThemeManager) {
			Msg.error(HeadlessThemeManager.class,
				"Attempted to initialize theming more than once!");
			return;
		}

		HeadlessThemeManager themeManager = new HeadlessThemeManager();
		themeManager.doInitialize();
	}
This is a strange implementation of {@link ThemeManager} that is meant to be used in a headless
environment, but also needs theme properties to have been loaded.  This is needed by any
application that needs to do theme property validation.
Ghidra/Framework/Gui/src/main/java/generic/theme/HeadlessThemeManager.java