You've just reminded me of a project I ran into years ago that seems to still be around: https://remotestorage.io/ https://remotestorage.io/ The library for th

You've just reminded me of a project I ran into years ago that seems to still be around: https://remotestorage.io/ https://remotestorage.io/ The library for that seems to support their custom protocol as well as Dropbox and Google Drive these days. There's also Solid which attempts to do something similar: https://solidproject.org/ https://solidproject.org/