The "Help"->"Help" menu item is notably unhelpful:
> For questions, comments, or suggestions, you can email support@gnuradioworld.com, join the Discord server, or post a GitHub issue.
"Help"->"About" at least starts to clarify some things:
> GNU Radio, entirely in your browser — explore the open-source SDR ecosystem with zero install!
> GNU Radio World is a browser-based GNU Radio Companion flowgraph editor and WebAssembly runtime. You can place, connect, and configure blocks, then run the resulting flowgraph directly in your browser.
> It is designed to download only the WebAssembly modules corresponding to the blocks you use. This on-demand architecture keeps the initial download small and can support a limitless collection of out-of-tree modules (OOTs) in the future.
> GNU Radio World also includes a collection of real RF recordings that are downloaded only when you use them. You can inspect the recordings in the built-in recording view, adapted from IQEngine, and use them in the included flowgraph examples, allowing OOTs to be shown off with real recordings of the corresponding signals