Store zero-access encrypted emails as PGP/MIME
I noticed that when viewing raw emails with the “View headers” feature, they are stored as essentially PGP/Inline emails, which causes trouble when dealing with HTML emails and emails with attachments.
It would be better if, upon receipt of an unencrypted email, ProtonMail wrapped the entire message in an encrypted PGP/MIME container, which would preserve any Content-Types and allow for easier future exporting of PGP-encrypted inboxes without having to deal with the issues that come with PGP/Inline. This would also enable possible future IMAP/POP3 support of the raw, encrypted emails without the ProtonMail Bridge, leaving the decryption up to individual email programs, instead, like GPG Suite, Thunderbird + Enigmail, et cetera. This in turn could allow ProtonMail to hold only the public keys to encrypt emails, leaving decryption completely up to the local mail clients and locally stored private keys, to cater more for advanced users. ProtonMail, at this point, would just act as a gateway to encrypt all incoming email before storing it, an option that would never be available on Gmail.