The HUD, or "heads-up-display" is the small text display at the top of the screen which includes informations such as temperature, pressure, particle which your mouse is over, version, and speed (in Frames per Second or "FPS")

HUD Enabled

To toggle this display on and off, press the "h" key on your keyboard, This can be used to enlarge the field of gameplay and visibility.

Disable HUD to free screen space