Status Button
From Starbounder - Starbound Wiki
The Status Button is mapped by default to the player's [Alt] key. When pressed down, all player nametags and NPC status messages will appear, and the game will highlight all objects that the player can interact with. While the button is held down, the nametags will remain visible and the highlighted objects' outline will pulse slightly.
The status button can allow the player to see NPCs and containers that would otherwise be hidden, which can be used to find nearby caves or hidden loot, especially when using [Ctrl] to shift the camera beyond the typical viewpoint.
