It means "in the Add-ons Manager, this addon's line, click Options." This opens the addons' detail page, and the options are under the description. If the options are not shown, refresh the page.
I just tested 2.0rc4 on Firefox 56.0.1, and the addon manager toolbar button works. As a Firefox-Quantum-compatible extension, this extension has no ability to block the browser's built-in features such as the addon manager button.