Hit Install and the mod lands in this browser, right next to your game files. Then pick it under Mods, above the Play button. If someone hosts a game with a mod you don’t have, just join it from the game list and the mod downloads first.
Checking this browser’s storage.
The desktop game works the same way. Mods go in the Mods folder next to your game files, or wherever you point --mod-root.
tak-re --relay ws://<server> --registry
tak-re --relay ws://<server> --install-mod tak-enhanced
tak-re --remove-mod tak-enhanced
Joining a modded game works here too. Press Join once to see what it needs, then again to grab it.