Apple’s biggest secret may be out: Documents have come to light that strongly suggest the company is ready to test technology for a self-driving car. “Project Titan,” as the operation is reportedly called, is all but confirmed. The Guardian obtained documentation of correspondence between Apple and GoMentum Station, a Silicon Valley naval-base-turned-autonomous-vehicle-testing-facility, in which Apple engineer Frank Fearon in uires about site usage. “We would … like to get an understanding of timing and availability…