Why does iOS create Group folders within CPLAssests folder on iOS?

Currently exploring the following file path:

var\mobile\Media\PhotoData\CPLAssests\group82

My understanding is that 'CPLAssests' indicates the original file is in the Cloud for that assocaited Apple ID, and only a '5005.jpg' of the original with EXIF data attached, is what's rendered to the user via the user interface. 

My question is, what user interactions occur for these 'CPLAssets' to be created, and why does iOS create these 'Group' folders? is there  a purpose? 

any help would be appreciated.