At the top of the Level Editor window, at the right side of the Tab Bar, you will find a series of performance and debugging tools.
From left to right, they are:
Console Command Bar
This text field is used to input console commands within the editor.
Source Control Status
This shows the current status of the integrated Perforce server.
This region displays the following information:
FPS: Shows the frames per second, as well as the current delta time (time between each frame).
Mem: Shows the current amount of memory in use by the engine.
Objs: Shows the current number of objects in the scene.
20 Second Playback
This saves a 20-second video of the last 20 seconds of work. A bar will appear at the bottom of the Level Editor showing the path to the video.