A recent comment was absolutely correct. Developer for some reason does not respond to reviews or is unable to. Not a good sign that problems with this app would be fixed in the future or updated.

v0.2.3 has disappeared somewhere for those who are using or have tried earlier versions without success. Fortunately I have managed to save it with FEBE in an earlier version of Firefox.

c'est pour la première fois que je pense qu'il corresponds à moi qui n'a pas utilisé des modules..;

I had high expectations. So downloaded and installed it.

Unfortunately it doesn't work, on my setup:
- macOS 10.14
- Firefox 63.0 (macOS)

When i click on the extension, a window (similar to the one of the screenshot) popsup, but it's empty except for a endlessly spinning wheel (Loading...)

Any idea why it's not working for me?

Thanks in advance for your reply

superbé