Lots of questions are pure physics questions and don't involve worldbuilding even if the situation is hypothetical.
Just today, that started this discussion. People designing settings on other planets might want to know what is "out there" and other characteristics about other kinds of stars etc. These are "real knowledge" questions with their own communities.
Likewise, hypothetical questions on non-exotic life forms can best be answered by a biologist, and sometimes questions are mundane real-existing-knowlege questions.
Science Fiction and Fantasy
What previous stories have used the idea? Or is it involving an existing "shared universe" rather than designing a new one?
Closely related! Often times general SF plot and character ideas surface here and need to be turned away.
Is there a reason to keep the list short? Or at least to keep it ordered manually rather than automatically sort by actual use? If someone asks a Chemistry or Economics questions once we can't migrate it because we didn't think it would be a common thing.