As Google hover over the nuke from orbit button on Stadia, they're at least releasing some of it as open source like CDC File Transfer.
Noted on their GitHub page, it's a way for syncing and streaming files from Windows to Linux. The question is: why another way to sync files? There's tons of ways that already exist. Well, they explained that too.
Developers could use scp, but they noted it was "impractical" especially with more people working from home as it "always copies full files". So they made cdc_rsync and cdc_stream to help developers who quickly iterate on games. Something that could potentially be useful for developers checking out stuff on Steam Deck too.
CDC RSync is designed for syncing files from Windows to Linux but optimized for existing files possibly being on the end machine. They go into detail on why and how it's different to rsync, including showing it performing better for this specific case because of how they split up files into chunks differently at variable sizes. While CDC Stream is for streaming files from Windows to Linux, they say it's "conceptually" similar to sshfs but "optimized for read speed".
For anyone interested in trying it out, they provide release builds for Ubuntu.