I'm often curious to see which websites were blocked when I do searches so I can evaluate my filters and make more informed decisions.
Having a small tooltip showing which base urls were filtered out when I hover the blocked results text at the top of search results would help with that.
A small tooltip showing which base urls were filtered out would let me decide easily if I want to adjust my filters or try without blocked results.
Right now I can just see x blocked results which doesn't provide enough info for me to make informed decisions about those search results and also my filters in general.