I'm also curious about ESX, Drum samples, and Apple Loops. I have two folders on my Mac that have the audio files. One is Macintosh HD/Library/Application Support and the other is Macintosh HD/Users/Sal/Library/Application Support. Which one is actually being accessed when loading the sounds in Logic?
Both are accessed when looking to load content, but the one in your user area is used when saving your own content. This is consistent with the majority of apps, where the /Library folder is for all users and the ~/Library folder is for your own user.