How Opera is caching web content?

My preferred web browser is Opera but I'm having hard time dealing with PC freezing whenever disk usage culminates to 100% (a frequent event now since I'm always opening many tabs similtaneusly). When trying to understand what is happening under the hood of the filesystem, I'm quickly lost among all these folders such as :

data/cache/data_01

data/cache/data_02

data/gpucache/

data/shadercache/

data/service worker/scriptcache/index-dir

I know what is caching and what is webstorage but I don't know where people who wrote Opera or Chrome code learned to design this cache system ?

Since this system seems to be liable for performance degradation (IMHO),I want to understand and modify it...

Is there any link for a book or serious forum explaining such "architecture" - knowing that many contents on the Internet don't give real answers