We bumped up against this only a tiny bit during the definition phase, so I'm glad this question is being asked.
Also, what follows is just my opinion, so if you disagree, please add your own answer, explaining why you think it should be different and we'll see how the votes play out.
My opinion is that questions related to specific software packages should not be allowed.
And my reasoning for this is that (a) we don't want to be tech support for a hundred different programs, and (b) it's a slippery slope.
Let me go into a bit of detail on both of those. Consider the question, "How do I export my world from [Program X] so that I can load it into [Game Engine Y]?" A question like this most definitely not about worldbuilding in any form or fashion. This might be on topic for something like the Game Development stack exchange, but it's a question that should probably be answered by the makers of Program X.
Even a question related to some aspect of actual world construction has problems. "How do I get [Program X] to generate a mountain in a specific spot?" is not really a worldbuilding question.
If the question can be stated in a way that is unlinked from the specific program, it's probably OK. "I'm using [Program X] to generate a 'Lonely Mountain' type situation, which I'm told only happens through volcanic activity. What differentiates a volcanic mountain in appearance from one created through other processes like earthquakes?" In this case, while the correct answer may map to certain attributes of the specific terrain generation tool, the correct answer can be determined in a way that is not tied to any specific tool.
To provide some detail about it being a slippery slope, consider the following. There's a broad spectrum of software out there that could be considered worldbuilding tools.
On one end, you have tools that are very generic. They're essentially just repositories for storing information about an abstract world or universe that you're creating, and perhaps some things built in to help you brainstorm or get ideas. An example of this is Aeon Timeline. While my gut feel is that I still don't want to be doing tech support for even this type of program, I could be convinced that it's OK.
But then you start drifting into the other side of the spectrum and you find yourself in the realm of world editors. Something like Minecraft, which in a sense is a whole game that's kind of about building a world, is already starting to get very questionable. "How do I wire up a pressure plate to an iron door?" seems very off-topic to me, and "How do I build mountains in Minecraft so that they look natural?" is only a little better.
Keep going down the spectrum and you get to things like "How do I put a bonus/prize in a block in [some Breakout Clone level editor]? Or even "How do I decide how often is too often to have an extra life bonus/prize in a block in my Breakout Clone?"
We want to keep the focus on worldbuilding. Using a level editor is, in my opinion, not worldbuilding anymore. If a person has worldbuilding questions that have come up while using a specific program, we want those questions. But if it's a question about how to use a tool that they happen to be using for worldbuilding (which are going to be legion), I think we have to send them back to the customer support of said program.
To the point of it being a slippery slope, it will be easier to draw the line at "We can't answer questions about specific software products for doing worldbuilding. We are focused on general worldbuilding principles and practices," than it would be to draw the line at, "We sometimes allow tool-specific questions, but it depends on [some stuff]."
That's my opinion anyway.