Chrome 68 is now a stable channel for Windows, Mac, and Linux. The latest Chrome 68 release includes new features and bug fixes. Earlier this year, Google announced its intention to provide a "Not secure" warning on HTTP sites. That warning has been implemented in Chrome 68.
Google has added a new AR API, the WebXR Hit Test API, to Chrome Canary, the version of Chrome where it tests bleeding edge, experimental functionality. The API is designed to "[help] immersive web code place objects in the real world" and provides a single API that performs a raycast.