What is ⏏︎ used for on the top right corner of the magic keyboard?

Used with Apple Super drive to eject CD/DVD. Will not work with other noon Apple CD drives (in that case just right click on Drive on desktop and pick "eject"

I’m pretty sure that is the eject button for Cd’s, etc.

⏏︎ is also used in some keyboard shortcuts. See the "Sleep, log out, and shut down shortcuts" section in:

Mac keyboard shortcuts - Apple Support