The company is using the developer preview to give beta testers a sneak peek into some new features, such as "notification channels," which will offer users the ability to group notifications. There is also Picture in Picture, which will enable you to have a video appear in a small window on top of homescreen or any application. Google is also adding "multi-display support" and improved "keyboard navigation." Your guess is as good as mine as to what these features will actually do. There's also better "background limits" which will supposedly help save battery, and wider Wi-Fi support to include things like Neighborhood Aware Networking (NAN).
No word on what "O" in Android O stands for.
Assuming it does indeed go ahead -- and with the Norwegian government having already set aside the money, this seems relatively likely -- the Stad Ship Tunnel will reach a length of 1.7 km (1.05 miles), and measure 37 m (121 ft) tall and 26.5 m (87 ft) wide. It's expected to cost NOK 2.3 billion (over US$272 million) to build and won't actually speed up travel times, but instead focuses on making the journey safer. Top-tier architecture and design firm Snohetta has designed the entrances, and the company's early plans include sculpted tunnel openings and adding LED lighting on the tunnel ceiling.