Minecraft wiki entry for Inventory, associated text: When sleeping or riding a pig, horse, boat or minecart and the inventory screen is accessed, the avatar is shown in the respective position. However, only the player is displayed.[verify]
In the Item Selection screen, some items and blocks are missing, such as dragon eggs‌[Java Edition only] and spawners‌[Java Edition only].
The avatar always looks at the mouse cursor while in inventory.
The Search Items tab's compass icon spins wildly in the Nether and the End dimensions, acting just like normal compasses and clocks.