“Steam Database has revealed images of what is supposedly a work-in-progress version of Steam’s ongoing interface redesign. SteamDB said the pictures were “leaked through an update to the Chinese CS:GO launcher”.”
This upgrade should make the Steam interface easier to navigate through.
It will also have a hover effect on the trading cards when you put your cursor over them.
The interface is currently in progress, some things may change from the preview you have in these pictures.