This is a complex issue of legalese and moderation. On one hand it would be great to support private file sharing, on the other it would allow for hosting of illicit content that can get the host into a hot water with the law. Blossom is in the similar situation with the different api, and I assume not all (or many) blossom servers will end up supporting any mime types. At this phase, you might as well implement S3 interface and just allow user to supply credentials. I’ll think about it but we need to ensure that there is a good balance of privacy and secrecy, which are not the same things.