Moves one file between two browsers directly. Open this link on the other device, or send it to someone else. The two sides connect to each other, not to a server.
On macOS 26 and iOS, this browser asks for Local Network permission as soon as this page opens. The page is getting ready: it has sent nothing anywhere, and no connection to another device has started. Answer yes, because that permission is what lets the two devices find each other on the local network.
Opening the room…