Resano od ImmortalVision

Resano forwards the SMS verification codes your Android phone receives to your computer, end-to-end encrypted. This add-on fills a recent code into the page you are on, when you click it or automatically if you turn that on. It never submits a form.

It needs the Resano desktop app, which it reaches only on 127.0.0.1. Codes never pass through the add-on's own servers; it has none.