Yeah, but also you can build browsers that only support portions of the specifications considering standards like CSS are broken up into various modules. You d

Yeah, but also you can build browsers that only support portions of the specifications considering standards like CSS are broken up into various modules. You don't need to build a browser that supports JavaScript, either. You could implement any other language you wanted. Python! C?! Go? Rust? Writing a toy browser that supports small subsets of web standards is fun, and not too difficult.