So apparently the Add-On SDK for Firefox extension development is being put to rest. WebExtensions are where it’s at. This is probably old news to many, but I’ve not been paying close attention. The new method is modeled after Chrome’s extension stuff and supposedly even Edge has a similar method.
Anyway, I spent Thursday and Friday of this week working on a little Firefox WebExtension. I’ve added a toolbar button with a popup dialog and some code to communicate with a background script. The next step is to use the “storage” part of the API.