Mesh_Tools_UV_Maps_Load_UV_Set - Diffeomorphic/import_daz GitHub Wiki
Load UV Set
Some textures are not made for the default UV coordinates but for some alternative UV set. This is handled automatically by the Daz importer if the materials are set up already in Daz Studio. However, you may want to change the textures of an already imported character in Blender, and then you need to change the UV set as well. This button loads an alternative UV set to the active mesh.

Here is an example of different UV coordinates for the fingernails.