spec isn't code. There's a C language specification and many implementations. There are a handful of browsers each implementing HTML, JS, and CSS specs in their own way.
And given a C description of a program, a C runtime can implement that program in various different ways — interpreted vs compiled, explicit memory management vs garbage collection, different pointer sizes and memory layouts, parallelism at various points or not. It's turtles all the way down :) It just becomes ‘code’ at the point where a computer can execute it (in one way or another) without further human intervention.
