Ah I see what you mean now. My mistake.

That sounds more useful... but it's also something that most developers could probably build for themselves in a few minutes?

1. Grab page 2. Parse and find links 3. Make a request to each link 4. Return any links that are returning 4xx or 5xx.

Maybe there's a use for it where people want to test a particularly large set of pages/links making use of a data center's typically superior connection? shrug