Unlike other browser-based x86 emulators, OSes running inside v86 can actually access internet via a transparent proxy relay. You can load your own OS images, or choose one from a pretty comprehensive list (Arch Linux, Windows 1.01 to 2000, SerenityOS, BSD, Android 1.6, Haiku, QNX, and so on).

The VM images are loaded in stages, so it boots fast. When you run a program or code that's not loaded yet, it'll fetch the image and perform a JIT compilation of x86 code to wasm. The delay when fetching additional images and performing JIT compilation is noticeable, but the program run fast afterward considering this is a full x86 emulator running entirely within a web browser.