Today I have been notified to update to the latest version of Flagfox.
I note the following:
Be careful with old versions!
The internal data base will become increasingly inaccurate so I should update to the latest version.
This add-on is not compatible with your version of Firefox.
But I'm not using Firefox, I'm using the latest version of Pale Moon version 27.7.2. After many, many years I left Firefox in favour of Pale Moon when it adopted the GUI they called Australis - the Google Chrome clone. I've been very happy with Pale Moon since (and Flagfox).
What gives?