What Is The Purpose To Have 2 Less Files For Same Theme?

In the back end, there are several themes css/less files if you follow this root "public_html/design/themes/responsive/styles/data". I can understand that these files are connected with Theme Editor in CS Cart admin. However, there is another less file for same theme in this root "public_html/design/themes/responsive/css".

What is the purpose to have 2 less files? What is the relationship between them? Which one has higher power to apply the style?

any help