Google seems to be finding a "sitemap-questions-0.xml" on android.stackexchange.com. However, when I go to click on it, I get a 404 error. Here's the link that Google gives me: https://android.stackexchange.com/sitemap-questions-0.xml
Here's a screenshot:
Is this an old result from when Googlebot did its crawling, or does the file actually exist but return a 404 to prevent regular users from trying to access it?