With a codename as cool as “Project Titan,” it was only a matter of time before somebody did some digging, and The Guardian has. With a public records act request, the media group obtained correspondence that more or less confirm suspicions, first reported earlier this year, that Apple is working on a self-driving car—and it’s way farther along than everyone thought.

It seems, in May, the secretive team of Special Project engineers met with the folks at GoMentum Station, a sprawling 2,100-acre high-security testing ground for “autonomous vehicles” just outside of San Francisco.

There’s been a number of times eyebrows were raised, eyes were thinned, and chins were stroked (with a bonus “Hmmm”). There was the time last year when Apple CEO Tim Cook toured BMW’s i3 electric car assembly line with Fiat-Chrysler’s head honcho. And there’s been the cryptic remarks made by Senior VP Jeff Williams, saying that Apple is currently “exploring a lot of different markets” and that the car is “the ultimate mobile device.”

According to The Guardian’s documents, the Apple automotive team is housed in a low-profile Sunnyvale building, miles away from the company’s Cupertino campus. Secrecy is a core component of Apple’s culture, inside and out. Even in the obtained correspondence, engineer Frank Fearon signs his emails with a question mark icon.

Apple knows that secrecy helps build hype, but it also helps build without distraction. We won’t know more about Project Titan for a while, because they’ll be hard at work, building a car and building it their way.

Get the full lowdown here.