A post on the developer's website revealed that it was "in charge of planning and developing the free update" for the sports title. The update launched earlier today (or yesterday, depending on your timezone), and gives you multiple ways to play this brand new sport. This brings the total number of sports in the game to eight. Coincidence? Well... yes, probably.
Eighting has a pretty colourful development history. The studio was formed in 1993 by former Naxat Soft and Compile staff, many of whom worked on the Aleste series. Over the years, it's worked with Hudson Soft, Konami, Bandai Namco, Capcom, and Nintendo on multiple occasions.
With Nintendo in particular, it developed Kuru Kuru Kururin and its two sequels, and Master of Illusion (or Magic Made Fun, co-developed with Tenyo). It's also responsible for the new content in Pikmin 3 Deluxe and co-developed Pikmin 4 alongside Nintendo EPD.
Other titles the studio has worked on are Bloody Roar, Tekken Advance, Castlevania Judgment, Marvel vs. Capcom 3, Monster Hunter Generations Ultimate, and DNF Duel. It's currently developing Hunter x Hunter: Nen x Impact and is helping with Marvel vs. Capcom Fighting Collection: Arcade Classics.