This makes me think of the problem text messengers have. Do they have one central server, or do they have a federation of independently run servers with differi

This makes me think of the problem text messengers have. Do they have one central server, or do they have a federation of independently run servers with differing software versions? If they have the latter, how do they encourage everyone to maintain a minimal standard level of compatibility? What if someone wants to introduce a great new feature? Does it take years because of the non-centralized nature and people refusing to update? What you envision about modularity in a small way has already happened with the Skia graphics api. "The library is used as of 2021 in Google Chrome, Chrome OS, Chromium OS, Mozilla Firefox, Mozilla Thunderbird, Android, Firefox OS, LibreOffice (from version 7.0), Flutter and Avalonia (from Alpha 4)."