I didn't see this mentioned anywhere else but in the Atari podcast they casually slipped it in at this timepoint: https://www.youtube.com/watch?v=WqtfN6ZcST0&t=2968s
The other insight I got from the podcast is that they're really gonna delve deep into the stories of the Tetris games not yet playable in the collection (the Atari collection had DLC so I'm hoping more might be added)
There's an even a video interview with Tetris Effect producer Tetsuya Mizuguchi who reveals something very interesting, that he originally wanted to make Tetris Effect back in 2005 (he envisioned a Tetris game with the sensory elements of Rez) but couldn't due to licensing issues, so he made Lumines instead… in theory we could've got Tetris Effect 20 years earlier!
by Max_MM7