I tried to live-update the RSS links as the page change, but sadely it's not possible due to this 2007 Firefox bug. If this bug is one day fixed, I'll re-add the code (stored in Git) for autodiscovery live update. For now, the links are in the static HTML code, to avoid this. At least it work for the first page and RSS readers.
This said, it's complete now I think. And translated in French, too.
And I noticed I forgot to give this pretty useful information (but that can be guessed):
composer require amaurycarrade/flarum-ext-syndication
Feel free to report any problem ? .
Update: extension official thread published.