The showdown rules of poker state that the player who took the last aggressive action on the final betting round shows their hand first. If everyone checked during the last betting round, the normal order of play is followed and the closest player to the left of the dealer shows their cards first.
The name itself is a bet on a downtown resurgence (the D stands for Downtown, get it?). Whether it succeeds or fails, it is extremely notable as the first new opening of note in Downtown in well, in forever.