Hi, I've tested this in 4.6. RC but it seems to be working only for really incorrect links.

If I link to a non-existing url on a WordPress installation I get a 404 error page. However this 404 error page is not marked as an error in the new broken link checker. It looks like the 404 error page is not noticed by this new feature.

Am I the only one who notices this? Or is this how it is supposed to work?