It pretty much feels like the file is just uploaded and a link (string) is generated to communicate that over sound. The receiving browser then just uses that "download link" to download the actual file. The file uri also just downloads a file from their servers.<p>Just saying, as it's not really mentioned on the site as far as i can see.
This is something with a completely unknown usecase to me but I'm amazed at how good it works and it seems like a really fun project, thanks for posting it!