[logback-dev] What's the exact difference between File and Presentation Header?

[Lilianne E. Blaze]

Hello,
I'm trying to write a custom Layout, I have it pretty much planned, but 
there's one thing I don't know - what's the exact difference between 
FileHeader and PresentationHeader? As in - which one is meant for what 
exactly? Neither the source nor Google were clear on that.

Greetings, Lilianne