@iska @clacke it depends. I found that if there is english documentation, it can help you. I am still trying to understand how well it understands the actual code and can synthesize answers to questions from the code. For example, when I ask for JavaScript code, it gives me clean and modern code. But if you look at source code for javascript projects, overwhelmingly it is written in "old" javascript style before ECMAScript 6 improvements that make everything more readable. Obviously Copilot was trained on Github so it must work but I am having a hard time understanding how it differentiates between older and newer style javascript. To tie it back to the question, if there is code and documentation then i bet it works.

side note: I also use it to explain complicated software specifications to me and answer specific questions about them .W3C specs are large and comprehensive and in understandable English. I ask it questions like "can X document type and Y document type be the same document" or "how and where is this document's location actually found before you can read it" or "does this spec allow this type be used" and it does a GREAT job of answering those questions, ften with references inside the documents. It is a MASSIVE time saver. When people talk about how does AI help coders, I wonder if they ONLY mean coding, as opposed to reading and understanding public specifications and standards you have to incorporate.