[Fixed]-Django Mezzanine CMS base urls.py location?

That is correct. Mezzanine page urls are not defined explicitly in a urls.py, but are stored in the database in the Page model’s slug field. You can navigate to the “about” page and the admin and modify its slug field there.

Note that in practice, page views are always intercepted and returned by mezzanine.pages.middleware.PageMiddleware, which could be relevant for debugging purposes.