WebAssembly was designed to be able to [run outside the Web] from its beginning.
"Universal Binaries". Things by this name have been made before,
many times. And things by this name are being made on top of WebAssembly
too.
- What kind of platform APIs are available?
- What's the sandbox model?
Because of course, you can technically achieve a single-file app that runs
on a wide variety of platforms.
Spectre, Meltdown.
Rowhammer.
[run outside the Web]: https://github.com/WebAssembly/design/blob/master/NonWeb.md