Freddy’s Bar and Backroom, once doomed to be the best-known casualty of the Atlantic Yards development, reopened in a chummy space just past the southernmost fringe of Park Slope proper. The very same scrappy booths, schizoid video mash-ups, and bar-back jackelope, taxidermied squirrel, and marlin as the old. In fact, the bar itself was transplanted from the former locale to the latter. To complete the experience, its back room hosts the usual mix of music, comedy nights, and low-key movie screenings. If anything, it’s even more relaxed than before: in adopting the sleepy nabe between South Slope and Sunset Park, it continues to grow a bit milder with age.