2. As said in 1, we have export now via multiple avenues. Some are paid, but the import/export tool certainly won't be for the general release and the bridge status may change too. It's taken a little while but there's no vendor lock-in and it has nothing to do with the protocol the tools use to talk to the server.
3. True, but part of open-sourcing is people building stuff to interface with the API and I don't want people building stuff on obsolete interfaces which might further delay dropping support for them.
2. The IMAP/SMTP bridge being proprietary and paid-only is really the biggest grievance I have with Protonmail. It's so mind-bogglingly unacceptable. I could forgive your servers not speaking IMAP/SMTP if the bridge wasn't like this. You should fix this and you should fix it yesterday.
3. People can reverse engineer it today and do the same thing. People have done this. You should just open it up already.
A bit of both, though the API restriction will be relaxed soon. We'd much prefer to open-source the bridge and have the community contribute there though. Hopefully we can get there soon.
3. True, but part of open-sourcing is people building stuff to interface with the API and I don't want people building stuff on obsolete interfaces which might further delay dropping support for them.