Is there a resource to learn WebAssembly?

I don't mean how to use a tool chain to compile higher level languages to WASM. I mean how to write the linear assembly bytecode as seen here on Wikipedia:

https://en.wikipedia.org/wiki/WebAssembly#Representation

No linear, but these ones are quite good for the Lisp-like syntax, which I prefer.

https://mbebenita.github.io/WasmExplorer/

https://wasdk.github.io/WasmFiddle/

I think these won't let you write WASM. Am I wrong?

Sorry I did not read it properly, you can use these ones instead to actually write WASM.

https://github.com/WebAssembly/wabt

https://github.com/cretz/asmble