Sorry if this is a repeat, couldn't find words uncommon enough to use in the search box.
I think being able to see where a site's sourcing its ads might be a good thing to know, and having a spotcheck on what's being blocked sounds comforting -- and if it sounds comforting, then something's uncomfortable. . .
Anyway, even if it turns out the information's useless, this'd help being able to discover that for yourself.