Firefox Android
Mobile device support is basically impossible until netcode.io support appears in browsers natively, as mobile platforms don't support extensions or native messaging.
Why is this not compatible with Firefox for Android, Opera Mobile? https://addons.mozilla.org/en-US/android/ https://dev.opera.com/articles/extensions-opera-mobile-labs/
Granted, over 90% of the market is on iOS Safari, Chrome for Android, still it could be useful to test - which I intend to do :-).
The native messaging part of WebExtensions isn't supported on mobile (at least in Firefox). We require a standalone helper with native messaging to actually send and receive UDP packets.
That said, we are working on getting this adopted in more browsers natively, which would enable support for it on mobile.