New user comments say, "this site's on/off-topic definition is kind of confusing compared to other SE sites", and, "I took the tour".
The "tour" must be a reference to the About page (because the hyperlink to that page from the Help button on the top-of-page banner says, "Tour - Start here for a quick overview of the site").
To what extent can this About page be customized? I guess that,
This part can be customized:
Welcome to Skeptics Stack Exchange
Skeptics is a question and answer site for applying scientific skepticism. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers challenging unreferenced notable claims, pseudoscience and biased results.
The rest cannot be customized (except in choosing the example questions and answers).
Can we improve either of the above?
- Some text to specify what's on- and off-topic
- A hyperlink to the Welcome to New Users answer (and/or other FAQ topics)
- Choose an example question which includes a notable claim (or especially create an example question just for that purpose)
The above page seems to me to suggest you can post any random/unreferenced claims/questions.