If you cruise by the Android developer site with any frequency, you may have noticed that it looks a little different. There aren't a lot of tiny individual adjustments, but rather two immediately obvious changes to the look and layout.
The major change here is a big new navigation drawer for moving around the site. Links to each of the major Android form factors (i.e. Android, Wear, TV, and Auto) are at the top of the list, followed by shortcuts to each of the major sections for Design, Develop, and Distribute. The hamburger button at the top left is functional. Clicking on it reflows the page and leaves it looking very nearly identical to the previous page aside from the bright green header.
The other visible change was made to the header bar, which still includes the Design / Develop / Distribute links. Google traded the drab white background for a thick layer of Android green. It's a bold addition probably inspired by branding, but it does a great job of calling attention to the search box and link to the developer console. However, it also takes some attention away from the great looking background photos belonging to some of the sections.
The latest version is above and the old version is below.
Left: previous version. Right: latest version.
Subsections are now directly accessible from the navigation drawer. In previous versions, they were only available as links running across a secondary header bar on the section pages. At the very least, this can save a page load if you already know which subsection you're looking for.
The Android developer site has always been pretty mobile-friendly, and the new navigation drawer fits in well. It's easy to reach and removes the need to scroll around the page to look for the Wear, TV, and Auto links.
These aren't huge changes, but they look more consistent with the Material design methodology and should make navigation a little easier, and they fit in well on both desktop and mobile.