Where is the line of topicality where WSL is involved?

Question

Q0: Where is the line of topicality where WSL is involved?

Q1: Now that Ubuntu can be run on Windows using WSL, I see many questions about windows-subsystem-for-linux Are these questions a better fit for a Windows-oriented site? If the problem is contained entirely on the Ubuntu side, I'd expect it's reasonable to ask here, as discussed in this question – Do we consider "Ubuntu on Windows 10" the same as an official Ubuntu flavour? Do we support it? To what extent?

Q2: But what if the problem is getting WSL working at all? That is, it involves the Windows side. For instance, this question appears to be about a problem with the Windows Store that may have nothing to do with Ubuntu: Cannot Install Ubuntu 18.04 WSL

Q3: I've been informed that "if you're using Ubuntu and trying to get it to do something, then you can ask about it here." So suppose I'm using Ubuntu on WSL, and I want to use it to process data from a Windows program. However, I can't get the program installed and working. This also appears to be entirely on the Windows side, independent of Ubuntu. However, since the intent is to use Ubuntu to process the data, would such a question about this scenario be appropriate here? For instance, this question is about accessing Windows-created Windows – Accessing Windows Display via WSL X Server

Note: I don't use WSL, so likely won't be asking or answering any questions like these. I'm curious about the rationale for drawing the line at various positions.

---

Stats about WSL questions:

• Total # of questions: 416
• Total # of open questions with no answers whatsoever: 93
• Total # of unanswered open questions¹ : 157

_{¹ Unanswered questions are questions that don't have accepted answers nor answers with 1 or more upvote}

Answer 1

I determine a topic-ness of a subject in two separate parts:

• It's about Ubuntu or one of its derivatives or anything related to them (which is precisely the quote you mention in your question).
• It's about an official Canonical product.

The second part is backed by the following text in the help center about the questions that we can ask about:

Questions that you may ask:

• [...]
• Services provided by Ubuntu and Canonical.
• [...]

WSL falls in the second part, which is an official Canonical product. So I do not vote to close as off-topic virtually anything regarding WSL. That also includes installing it on Windows. Whether it's better suited to be asked on a Windows-specific Q&A site is irrelevant in my opinion. Same reason as to why Ubuntu questions can be valid on Ask Ubuntu and Unix & Linux.

This reasoning of mine falls back to when Canonical had the, now discontinued, cross-platform Ubuntu One sync product. Any questions about that product used to be on-topic such as How to install Ubuntu One Windows Beta on XP?.