uBO has documentation to so called Blocking modes. I myself go even a step further and disable Domain and Inline scripts by default, basically whitelist mode instead of blacklist (about 1/3 of pages work better that way, if you only want to read the fucking text).
Are there matching filter lists who enable scripts/content for respective domains, at least for medium and hard mode? some Webapps like microsofts are a pain to deal with manually, with all their redirects.
And has some incompatibilities with modern FF features, no?
What modern features do you mean?
The only problem I’ve noticed since uMatrix stopped getting updates is that I now have to Ctrl+Shift+R instead of just Ctrl+R to get scripts to work after adjusting a site’s permissions.
Some webextension features & security stuff i believe? Someone once explained it in length here, a few months ago.