How a version gets here
- Fetch the real jar.
tools/fetch_af.pywalks Mojang's version manifest (and the Omniarchive vault, for 2.0, which never had a public download), downloads the client, and refuses to keep it unless the SHA-1 matches. - Take the jar's own assets. Textures,
en_US.lang, the panorama, all 318 splashes — overlaid onto the engine's resource tree, then packed into a singleassets.epk. - Bake the engine ahead of time. The singleplayer engine is compiled from Java to JavaScript with TeaVM, so the page ships a client rather than starting a JVM.
- Turn multiplayer off. Not greyed out — absent. No server-list button, no Share to LAN, no relays, no WebRTC voice client in the bundle.