Github: https://github.com/suitenumerique/docs
Self-hostable, but it seems like an absolute behemoth of an application if their "non-production-use-only" docker-compose file is to be believed, and I couldn't find any production-ready deployment instructions on a quick skim. No obvious signs of federation and I didn't see anything on their roadmap, not sure it would make a lot of sense for this though.
Windows prefers to deactivate or minimize the write cache on removable devices, most of the common Linux distros generally don't make such changes. Microsoft has a very good reason for that default: not a lot of people actually use the "safely remove hardware" option and if the cache is enabled, using and waiting for that is a hard requirement for the data to have actually made its way onto the drive.