is an open standard that defines a portable binary code format for executable programs, and a corresponding textual assembly language, as well as interfaces for facilitating interactions between such programs and their host environment

WebAssembly - Language Formats

binary format (.wasm)
textual format (.wat)	s-expression-based textual format https://developer.mozilla.org/en-US/docs/WebAssembly/Understanding_the_text_format

WebAssembly (WASM)