The first feature is a new look of timeline and new navigation controls. The timeline is less cluttered with lines and in its upper part there is just enough space for a group of buttons which control zooming and scrolling.
Zoom in and zoom out do what they say. "Start" and "End" will scroll the chart so that a project start date or end date will become visible. "Today" scrolls the chart so that your current time is shown. The most interesting button is "Scroll". It show a popup pane with a small overview of the whole project timeline and highlighted currently visible portion.
Well, that's not really new feature, you might have seen it in M2. But now it supports keyboard navigation. Using arrow keys you can scroll the chart to the left and to the right smoothly, with Page Up and Page Down you can do bigger jumps, you can even zoom in and out using Ctrl+ and Ctrl- keystrokes. And you can just click in any point of the overview pane and scroll the chart directly to that date. A tooltip will show you the date under the mouse pointer.
