Last year Proton talked about this and they say they were planning to add it to github repository, but still nothing : Reddit - Dive into anything
As we have no guarentee that Proton Calendar is 100% E2EE (no one can check the code), it is heart breaking for me to suggest to temporarily remove Proton Calendar from PG.
So the web source is available, isn’t it a problem if the source code isn’t available for other devices (Android, iOS…) ?
Instead of removing it, we could maybe add a note next to Proton Calendar’s section to say that the source code is not available yet for other devices (not updated since 2021), if you think it could be important for users to know.