The FBI has charged a former Apple employee with theft of trade secrets.

He worked on Apple's self-driving car project, Project Titan.

The FBI's criminal complaint reveals that Project Titan is significantly larger than previously believed, based on the number of employees with access to information about the project.

A Chinese engineer was boarding a flight from California to Beijing on July 7 when he was yanked off at the last minute by an FBI agent.

It's not a spy movie — it's a real life story of trade secrets allegedly stolen from Apple, an American icon, for the purposes of potentially handing them to a small, relatively unknown Chinese company.

Those secrets are related to self-driving cars, one of the hottest technologies in the world. Every major technology company is working on some project related to cars that drive themselves, but Apple's work in the space is particularly high-profile because of its secrecy and its reputation in Silicon Valley.

Self-driving car technology is valuable enough that Alphabet and Uber publicly fought in court over a $680 million deal that allegedly included Waymo self-driving trade secrets.

In this specific case, the FBI alleges that Xiaolang Zhang, a hardware engineer who used to work for Apple, stole trade secrets related to the company's work on self-driving car technology. He planned to work at Xiaopeng Motors, a little-known Chinese startup backed by Alibaba.

Although Eric Proudfoot, the FBI agent investigating the case, said that the information in the Tuesday affidavit does not include every fact he's aware of, the complaint filed on Wednesday is still an incredible look behind the secrecy curtain into Apple's car project, as well as the security at Apple's Cupertino headquarters. The FBI had extensive cooperation from Apple, according to the criminal complaint.

Zhang faces up to 10 years in prison and a $250,000 fine if he's found guilty of the federal felony of theft of trade secrets. His lawyers requested a Mandarin translator.

Here are 7 things we learned from the document:

Apple was designing hardware specifically for self-driving cars, including a proprietary chip

The affidavit says that Zhang's role was on the Computer Team, and he designed and tested circuit boards to analyze sensor data. A 25-page PDF he allegedly pilfered contained electrical schematics for "one of the circuit boards that form Apple's proprietary infrastructure technology for the product." An employee also showed Zhang a "proprietary chip."

Apple has 5,000 employees who have been told about "the Project," likely the self-driving car project

According to the complaint, 5,000 of Apple's 135,000 employees are "disclosed" on a project which is likely Project Titan, Apple's project name for self-driving car technology.

That's a significantly larger number of employees than was previously believed, although it's possible that these employees have only been told about a small portion of the project, such as cleaning digital maps for self-driving cars.

Previously, the best public estimate for the number of Project Titan employees was 1,000.

"Disclosed" — how Apple handles secret projects internally

The complaint also has a lot of information about how Apple handles "disclosure," or an internal term that describes when an employee can be told about a top-secret project, according to former employees.

According to the complaint, a manager needs to "sponsor" an employee before he becomes "disclosed" on any given project, whether it's Project Titan or Apple's augmented reality division.

Asking whether an employee is "disclosed" is not an uncommon conversation at Apple, according to former employees.

Apple's self-driving groups are organized under a "Research and Development organization"

There's still a lot of mystery outside of Apple how it organizes its automotive project within the company. Apple has what's called a "functional structure," where employees report up to an executive depending on what their skill is.

Software engineers, for example, are usually in Craig Federighi's group, because he's Apple's senior vice president of software engineering.

Apple's self-driving group was reportedly led by Bob Mansfield, an Apple old-timer who had to be coaxed back out of retirement. But it was less clear where it ultimately fit inside the company.

One line from the complaint, however, suggested that it is under the "research and development" organization.

Apple closely tracks the number of employees who can access information from its systems

One key piece of information underpinning the government's case against Zhang is that Apple recorded the number of times he accessed information from "disclosed" internal Apple databases after he had resigned from the company.

According to the criminal complaint, apparently Zhang generated "581 rows of user activity" two days before he resigned, according to Apple Information Security.

Apple was building prototypes and had requirements for power, battery system, and "drivetrain suspension mounts"

Some of the technical PDFs that Zhang allegedly stole described requirements for a prototype. Although Apple has publicly alluded to its car project, it has never confirmed that it planned to build custom prototypes of any car parts, including sensors.

Apple has secrecy training specifically for its self-driving car project

In addition to the secrecy training for new hires and interns when they join Apple, apparently the self-driving car project had a separate secrecy training, too.

Read the entire document below: