What is the constraint that is enforced on extents corresponding to types in the type hierarchy?

In windows explorer, select the file, folder, or groups of files and folders you'd like to copy. you can select multiple files or folders in several ways: click the first file or folder you want to select, hold down the ctrl key, and then click each additional file or folder you want.

Learning about them i guess, idk

The number on e is a ik that one