AFAIK, Mailbox.org was once open source, but has not very recently become closed source. PrivacyGuides.org recommends it, as does Tresorit (encrypted cloud storage), for example, which is closed source and is one of the services I use. Providers that implement encryption, have been audited, have been on the market for years, and have a clean track record of security or privacy scandals, which there aren’t many of these types of services these days. But I personally don’t like them and try my best to avoid closed source softwares as well.

In conclusion, PrivacyGuides mostly recommends open source software but also recommends some that are not based on their features, reputation, security and maturity.

Tuta has already been through some cases linked to German court orders to decrypt emails received in the inbox of alleged criminals, just like any other company that is subject to the legislation of its respective country (I don’t know the difference with Proton, which until now I only found out about the delivery of IPs, not the content of the emails themselves, based on Swiss court orders), but I don’t believe it is a honeypot because Tuta has clarified the entire issue and still has credibility in the privacy community.

Mailbox.org is closed source unfortunately and I believe the Client is too

Sorry. I’ve already added it.

https://www.reddit.com/r/ProtonMail/comments/1i2ff6q/call_for_andy_yen_to_resign/

UPDATE: Andy Reply

According to Andy’s logic, if Hitler were the president of some unfortunate country, we should differentiate the boss from his good nominees. Even using a company founded by an entire community to show a good evaluation made by one of its founders to give him a loving pat on the back and show the world that he is not completely bad as they think, but not meaning that the founder agrees with all his innocent actions, of course, such as disregarding the rights of many people around the world because they are just part of the democratic game.

Really disappointing. Never imagined this from Proton. Truly dead to me now.

Abandoning the Proton subscription now. How stupid and irresponsible. In fact, are running away from all your principles.

I don’t use any of these services and the app I use to check network traffic, PCAPdroid, reports that it is “com.android.mtp”, the one in the screenshot. Seems legit to me.