This makes me think that something like Stack Overflow could be used to train a model that generates code to answer a question—and that software specifications

This makes me think that something like Stack Overflow could be used to train a model that generates code to answer a question—and that software specifications that are decomposed into a series of requirements or "questions" could be fed into this model to produce code that's equivalent to a team of remote contractors. Your model would be based on NLP/votes of the questions, NLP/votes of the answers, and separating the text from the code in both. The fact that many markdown/code formatting tools have you select the language for syntax highlighting is useful for classifying code as well.