One redditor asked about it on the most recent AMA:
Hi, is there a plan to release protondrive for linux?
Proton CEO’s answer:
We’re currently looking at options for how to fund this. It’s an expensive development because Linux has so many different flavors and we need deep integration with the filesystem, and it is not yet clear if there are enough Linux users that would allow us to offset the cost of this development. Like many things Linux, it may eventually just have to subsidized from Proton’s reserve budget. That doesn’t mean it won’t get done, it will just take longer since we are also subsidizing several other efforts at this time, such as the Proton VPN free servers for elections campaign: https://protonvpn.com/blog/free-servers-before-elections
-Andy
Source: https://www.reddit.com/r/ProtonMail/comments/1ff211y/comment/lmrdepr
Would it help them to just pick a single distribution, open source the client, and have the community figure out how to build for other distributions?
Edit: also, part of the reason there aren’t many Linux users is because there’s missing clients Edit2: they wrote this in the AMA: On your first question, we are in touch with the rclone dev working on Proton Drive integration and they have our API specs and documentation, and we’re available to answer any questions that they might have
Yeah I agree, package it once and let the community do the remaining work. I believe that’s how steam was introduced to Linux, I don’t now where we are currently.