I am following a project called the Commander X 16, a Commodore 64 inspired machine based on, but only somewhat compatible with it.
My question: Is such a retro inspired development in scope of this stack exchange group?
Expanding on wizzwizz4's answer and the comments on it:
Questions about the actual workings of the C64 are obviously on-topic, even if phrased as, "The Commander X 16 works this way; does the C64 work the same way?" (I would not necessarily suggest phrasing things that way, but it may be useful if you're referring to some good documentation on the X 16 that saves you a lot of explanation.)
When it comes to porting C64 code, "How do I do this on the X 16?" is not on-topic for the group. However, if your problem is that you have a chunk of C64 code and you don't understand entirely how it works, posting a "How exactly does this work on the C64?" question would be right on topic. You'd need to ask a separate question elsewhere if, once you understand how the code works on the C64, you don't understand how to achieve the same effect on the X 16.
So perhaps the general questions you should be asking yourself before posting here a question inolving a "modern" system are, "Does answering this question require specific knowledge about a an actual retro system?" and, "Can I split this question into two, one for Retrocomputing dealing with the retro side and one for another more appropriate forum dealing with the new system side?"
While not yet being a "real thing" atm, the X16 is purportedly supposed to have:
The design reminds me very much of an MSX computer, but with a MOS CPU.
These all require programming techniques no longer taught to developers - Where else should such questions be asked?
If it looks like a duck, walks like a duck,... I don't care what year it was built.
Only to the extent that it relates to retro systems.
So, you could ask about how the Commodore 64 functions, or how to interface the two machines, but not how to change the Commander X 16's batteries.