UV Set Editor

Navigate to Create UVs > UV Set Editor.

The UV Set Editor lets you create and edit UV sets for multiple polygon meshes simultaneously.

The UV Set Editor lists only the UV sets for the currently selected polygon meshes. You must first select the polygon meshes in order to edit the UV sets.

New

Creates a new, empty UV set on the currently selected objects. You can then create the UVs in the set using one of the mapping/projection methods. This feature is the same as Create UVs > Create Empty UV Set. For information, see Create UV Set options.

Rename

Lets you rename the currently selected UV set.

Delete
Deletes the currently selected UV set.
Note: Maya won't allow you to delete the top-most entry in the UV Set list. If you do need to delete this entry, you can move it lower in the list and then delete it.
Copy

Creates a new UV set based on an existing UV layout or transfers a UV layout from one set to another. This feature is the same as Copy UVs to UV Set.

Propagate

Assigns the selected UV set from the UV Set Editor list to the selected objects in the scene. The selected UV set becomes the active UV set for those objects.

Unmapped

Selects unmapped faces on any selected objects in the scene. This aids in visually determining any areas where texture maps do not appear or appear incorrectly.