New York, New York - After putting Swifties to work on millions of puzzles, Taylor Swift has finally unlocked the 1989 (Taylor's Version) vault... most of it, that is!

The 33-year-old singer sent fans on quite the mission on Tuesday, tasking them with 1989-themed puzzles to solve via Google and promising that once 33 million puzzles were completed, she would unlock the vault.

On Wednesday, Swift confirmed four of 1989 (Taylor's Version) vault track titles:

• Is It Over Now?
• Now That We Don't Talk
• Say Don't Go
• Suburban Legends

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As has become re-recording tradition, the vault songs are tracks that were written during the creation of the original record but didn't make the final cut.

Though the puzzle challenge was promised to unlock the vault, Swift never likes to keep things simple, and one vault track remains a mystery. However, her team has confirmed that this remaining song is connected to the post that Swift shared on Instagram, which revealed the letters T, S, U, and L, along with two quotation marks and an exclamation point.

Also notably missing are any featured artists on the vault tracks. Swift has included at least two collaborations within each of her re-recording vaults so far, so it's unlikely that they will be omitted this time around.

Never failing to show off their slightly unhinged sides, extremely eagle-eyed Swifties noticed that certain letters within the 1989 Google puzzles appeared to shine.

Among those letters, fans quickly found one potential featured artist: boygenius. The indie supergroup consisting of Phoebe Bridgers, Julien Baker, and Lucy Dacus has gotten some public love from Swift in the past, and the trio even hit The Eras Tour stage in Nashville when Bridgers served as an opening act.

Still, there's a good shot there will be another feature, with Harry Styles, Nicki Minaj, Gracie Abrams, and MUNA among fans' top predictions.