@Override
	public void initializeOptions() {

		options = tool.getOptions(getOptionsCategory());

		options.setOptionsHelpLocation(new HelpLocation(HelpTopics.CODE_BROWSER, "MouseHover"));
		HelpLocation help = new HelpLocation(HelpTopics.CODE_BROWSER, "ReferenceHover");

		String hoverName = getName();
		options.getOptions(hoverName).setOptionsHelpLocation(help);

		options.registerOption(hoverName, true, null, getDescription());
		enabled = options.getBoolean(hoverName, true);

		options.registerOption(hoverName + Options.DELIMITER + "Dialog Height", 400, help,
			"Height of the popup window");
		options.registerOption(hoverName + Options.DELIMITER + "Dialog Width", 600, help,
			"Width of the popup window");

		options.addOptionsChangeListener(this);
	}
A hover service to show tool tip text for hovering over a reference.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/hover/AbstractReferenceHover.java