I just released Matchbox 0.5 (painless p2p networking for wasm)
Native-to-web cross-play is now finally supported :D And a nasty Firefox issue is also gone.
Here I'm dogfooding the feature in #cargospace starting a three player session between chrome, a native windows build and firefox on my phone (streamed back to my computer for capture).
Thanks, everyone who contributed!
Naughtylus 