Lookup codes are names that you can give to slices to make it possible to easily find a slice in a plotscript.

Press Enter to browse and edit the list of available slice lookup codes.

You can also type in the ID of a lookup code, or switch with LEFT and RIGHT.

Also, you can edit the name of a lookup code by typing, without needing to enter the code browser.

For more information, check out the plotscripting documentation for the "lookup slice" command.