I'm interested in learning more about the purpose of each folder underneath /System and /Library.
Some are more obvious than others. /System/Library/Fonts are a basic set of fonts for the system, and /Library/Fonts are any additional fonts available system-wide. But what's the difference between Frameworks and PrivateFrameworks? Can I do anything with the packages under /Library/Receipts? If I install a new app, where under /Library might I find the different dependencies of that app (Frameworks, Extensions, anything else?)
I suppose I'm really just looking for a list of every standard folder under /System and /Library along with a few sentences about what it is for and what might be found inside.