There was a web browser add-in (since deleted) that processed any news page you were on and added a red square around the names of authors and by-lines of people known to have a Jewish background. That add-in was deleted, though it seems to me all it was doing was adding information that people were free to ignore.
I'm not going to care much whether Facebook or Twitter (I don't really use the latter) adds 'fact-checking' to their list of 'services', though it would be annoying more than anything. Perhaps they'll give people the option to turn it off, or perhaps there will be some codenerds that can hack it and turn off the feature itself, like blocking ads.
No browser developers are compelled to host your antisemitic plugins in their app exchange. Your speech is free even when other people don't help you distribute it. No one can be compelled to help you