On itself you could ponder on why you need this...
Apart from being insatiable curious that is...

But if you want to block ad servers for example?
Did you ever notice they got these very cryptic, non-descriptive names?
PITA right?

Well, uBO-Scope can helps loads there I noticed when I tried it. So you can identify what that URL is (e.g. postrelease.com, hummm, well, look in uBO-Scope, and find it's an ad server).
So with that info, you can set-it-and-forget-it in uBO or uM.
Cheers Gorhill!