browser console Ctrl + Shift + J, not very useful for development, but some content script errors are logged only here (it’s a bug)
web-console Ctrl + Shift + K, useful for debugging addon page or content scrip injected into current page
background console (I guess?? ), it’s opened from about:debugging page when you click the “Inspect” button. This one is very useful as it prints all messages from all parts of your extension (except content scripts I think). It also allows you to change what context it is debugging (like pop-up), but it doesn’t always work well, so use to debug background scripts only. When you need to debug popup, it’s often easier to open it in a normal tab instead
In general debugging in Firefox is not perfect and sometimes you just need to restart your Firefox to make things work again.
Debugging should work the same every version. But sometimes it’s just buggy. Did you tried to restart Firefox? That often helps.
And maybe use “web-ext run” to run the extension - it opens new Firefox window with empty profile so things usually works there as expected .
No, but it makes thing easier. It has many features - by default it will auto-reload your extension when the source code changes.
But it can do much more and it’s really easy to use. Just open console in your source code directory and run web-ext run and that’s it. Really highly recommended .
So did you managed to see the source files in the debug window? If not, could you post a screenshot of your debug window?