Proton’s privacy policies state that they retain unencrypted metadata (addresses, timestamps, etc.) which are required to provide the service. This information may be disclosed to law enforcement. However, the actual content in your account is largely end-to-end encrypted. Law enforcement might request it, but without the keys to decrypt it they won’t be able to read your data.

Wasn’t their whole marketing point that they’ll have nothing meaningful to give out since everything’s properly E2E encrypted? Not sure how much the compliance rate matters when the provided data is useless. (They would need to comply in order to remain legally operating…)

I don’t disagree with you, but sending and receiving emails requires transmission of unencrypted metadata. There’s no easy way around it