Last month it was reported that Apple was planning a serious revamp of the MacBook Pro, including integrating the Touch ID fingerprint scanner into the laptop. This is a pretty wild rumor by MacBook standards, but there might be some evidence for it hidden in the code of macOS Sierra — the latest version of the company's desktop OS announced earlier this week.
As noted by 9to5Mac via MacGeneration, the macOS Sierra beta code includes a number of new resources, including a few prefaced by the string "kIOHIDBiometric." These end variously with "DoubleTapTimeoutKey," "TapTrackingEnabledKey," and "TripleTapTimeoutKey," which are all relatively oblique, but you can't really mistake that "Biometric" reference. That certainly suggests that Apple is prepping the Mac for some sort of biometric integration, be it built-in Touch ID or through a separate device.
Other new resources in the code have been rumored as possible controls for an OLED touch panel, but according to a report from French site Consomac this probably isn't the case. Consomac notes that these resources may have been moved about in the beta code, but are actually USB constants — nothing to do with OLED touch panels.
In any case, the existence of snatches of code doesn't ever guarantee new hardware features. It does happen, though, and in 2013, a number of resources in the beta for iOS 7 pointed toward the next iPhone having a biometric fingerprint sensor — something that came true months later with the iPhone 5S. Unfortunately, the very earliest we're likely to hear anything official about a new MacBook will be in September, when the next iPhone is announced. Until then, we'll keep our eyes peeled for more rumors.
Correction June 15th, 13:06PM ET: We've updated this article to include new information about the parts of code that supposedly related to the OLED touch bar.