"CONTAINSX" Revisited: What WAS the Match?

Last week's post on "CONTAINSX" proved to be quite popular. In the comments, Sasha provided an alternate formula that used FILTER instead of SUMX. Honestly I have a been of a "fetish" for SUMX - after all it IS the 5-Point Palm Exploding Function Technique - so at first I was like "nice work Sasha but I'm sticking with my SUMX." But then "en" asked if we could write a formula that reported what the matching keyword actually WAS - not just whether there WAS a match.