Well, I believe you already know the purpose of XCache
so I’m not going to talk about the conceptual issue here.
Some facts about this: I used the XCache
Long ago from that time until now it has little evolved the documentary question, there is very little content about it. Many thought the project was dead until the last update in late 2014.
About how it works: it works this way even if you spoke, just install and make the file settings ini
respective. But you can overwrite just like you do with some php directives for some particular script/application (like you did in the example).
this post explained in detail the most common directives of XCache
https://stackoverflow.com/questions/20087650/configuring-xcache-cacher