For some reason I have it in the back of my mind that they were at one point accused of being a honeypot for US intelligence because of their association with MIT. Probably complete BS, but maybe not. Are they as open source as they claim to be? Looks like they’re on github. F-Droid seems to think they have some Google libraries or whatever that they use.
ProtonMail users, how do you like/dislike it?
Email was designed decades ago, before the concept of data-mining even existed. It probably didn’t occur to the creators how universally accepted it would be. Much less rampant.
That being said, its’ privacy is entirely dependent on who stores your data and whether they give a shit.