godot parent
I think in their case, offline is as in you don't need to set up a pubsub server and the client doesn't have to talk to a server for the specific pubsub functionality, not as in "use this for offline web pages/html files locally" (it may or may not work for that, I have no idea, didn't look).
Works for offline apps as well :) (you would need to download the tabsub JS ofc and not use it from my server)