The latest version of the Chrome Dev Android app now comes with the new Chrome Home layout automatically enabled. Which means that after updating, the app will automatically open with a very different look and feel, compared to before the update. Chrome Home stems back to last October when the first traces of the flag were noted. However, back then it had to be manually enabled by the user. This is no longer the case.
As for what the new layout brings, there is quite a lot, although the common aspect is the inclusion of a bottom-positioned navigation bar. Something that has now been routinely showing up in many Google-related apps lately. So the first thing to note is that the new layout includes a dedicated bottom navigation bar, which in turn houses dedicated Home, Downloads, Bookmarks, and History, tabs. In addition, the new layout also includes a pull down (or arguably, a swipe up) format. If a Chrome browser tab is already open, then swiping the tab down will now close the tab. Likewise, if no tab is open then the address bar and settings will be positioned at the bottom of the screen. Clicking the + icon will then automatically swipe up and open a new tab. The new tab itself will also look different, with the quick link (most commonly visited sites) appearing at the top of the page, and the recommendations listed below. Once the new tab is open though, the URL bar does revert to the top of the page, as it did before.
As mentioned, this is currently only enabled automatically in the alpha versions of Chrome. So unless you are running Chrome Dev or Chrome Canary, then you are unlikely to see the new changes taking effect automatically. Although, with this becoming a default feature in the early versions of Chrome, it does stand to reason that it will become available by default in the more stable versions of the Chrome app (Beta and Chrome) in due course. More than likely when they hit version 61, as the current Chrome Beta app has only recently been updated to version 60.