Kbins original upvotes. Lemmy and Kbin are very similar but not identical, and they used different systems for their votes, so when they federated Kbin had to bodge their systems a bit, which is why the upvotes on Kbin are actually your favourites. It also means while downvotes (reduces) decrease your reputation, “upvotes” don’t increase it, only boosts do.
It makes more sense if you think of it more like Twitter with downvotes - Boosts were Likes and Favourites were Bookmarks.