SunRed

I created an account there an eternity ago when I first heard about them to reserve my username just in case but I will never consider a platform that cannot package their launcher/tool/software correctly and instead shoves a complex curl-to-bash script embedding binary data and a whole lot of other anti-pattern up my throat that is the least trustworthy and safest method of distributing your software.

This concept is also known as Double Blind Passwords or Horcruxing.

But isn’t this exactly what the Protonmail bridge is for? I don’t use Proton myself (self-hosted Mailcow) but afaik Imap doesn’t support public keys/PGP the way Proton is using it, hence one needs the bridge to use normal Imap clients like Thunderbird.