Unable to find resources in Asset Finder

Hi,

I was looking to customize the asset finder in aem 6.4. I was using the below path to look over existing fields used in asset find but unable to find these. Path which is am using in my search is /libs/cq/gui/components/authoring/assetfinder

Can someone tell me from where below highlighted section are rendering. Moreover how to add some custom action in that.

Thanks