The fraction sitemap.xml/undefined converts to NaN% when expressed as a percentage. This value shows up as “Not a Number,” meaning the calculation doesn’t produce a real numeric result.
In everyday terms, a fraction like sitemap.xml/undefined doesn’t have a clear denominator, so standard math can’t give it a sensible percent. It’s similar to trying to divide by zero, which leads to an undefined outcome.
Because the result is undefined, you’ll see NaN% in reports or tools that try to display it as a percent. It’s a reminder that the original fraction can’t be measured in the usual way.
