After rolling out its password manager to a limited number of users in April, Proton has finally released the service to the general public. The tool, called Proton Pass, uses end-to-end encryption to keep your usernames and passwords away from third parties, including Proton itself. It also lets you create and store randomly generated email aliases that you can use in place of your real address.
Proton open source is mainly a marketing facade.
All the code is in a giant repo all mixed (drive, email, and so on) with no documentation whatsoever. Technically it’s open source, but you can’t take it and self host the service like you can do with a real open source product
Edit: I just watched and it’s even worse than I imagined. No server components are open sourced and the client parts are hard coded to access the official servers. It’s like if I say “this car is open source. Except the engine, all the parts are proprietary design to work only with the secret engine, and anyway there aren’t any instructions, good luck with your diy”
I guess to me, being open source is more about the ability that it can be audited. I don’t care whatsoever about hosting my own proton mail / drive / vpn (which I use constantly all the time) but I do care if it’s audited and secure.
That said, I know they claim to be open source and audited, but I’ve never double checked those claims. Probably should.