We don't use more tracking than the usual website. And as you noticed, that gets blocked by tracking blockers anyway. We don't track the sites you're visiting, neither do we store your text. Plus you can run the LanguageTool server offline. Doing completely without tracking would mean we have no idea what issues users run into. Even add-ons with many users rarely get high-quality bug reports, so we have to rely on the anonymous tracking.

Thanks for your review. You can find the "English (British)" in the options under "experimental settings" and then "Interpret English as".

We have released version 2.0.25 which improves performance a lot - could you try with that?