A Loot box (or "Loot window") will pop up whenever a player right-clicks on an lootable corpse in range (or uses the engineering-only [Loot-A-Rang]). Inside the box are the items that the enemy held and that you can now take. The loot box also pops up when you fish, collect herbs from a plant or enemy, skin an creature, mine a node or enemy, or use your engineering skill on an enemy to collect items. There are also quite a few others, such as when using Archeology and collecting an artifact or when opening chests.