A R.I.C.E (Race Inspired Cosmetic Enhancements) according to the urban dictionary is
"Parts put on cars to make them look fast"
In linux terms 'rice' is used to describe a person's unix desktop where someone has customized their desktop such as the icons, panels, or system interface. A great place to find different linux rice is the r/unixporn subreddit.
Setting up a rice takes a lot of work. You need to install, copy the themes to their specific folders and if you find a rice you like it could be hard copying the file to the specific place if you're a noob in ricing. Wouldnt it be simple if you could just download one file which you can install on your system with one click without wasting your time copy pasting the several dotfiles and setting up the rice. For more information take a look at the wiki
If the app has intrigued you you can install it by running this command in a terminal to install themesaver.
Note: Only the following Desktop environments and Windows Managers are supported:
wget -qO- https://raw.githubusercontent.com/techcoder20/ThemeSaver/main/install.py | python3
I got the icons for the app from flaticon.com so here are the attributes for them :)