lucy24 - 7:32 am on May 11, 2013 (gmt 0)
In many cases, it's actually the order in which they are loaded.
I had the impression this changed between 1.3 and 2.2-- and I think I've hunted down the source [webmasterworld.com] of this impression.
Don't look at me. I didn't pick that shade of yellow.
I'm sure he said the same thing many other times over the years, but this is the one that bobbed to the surface. It helps explain why apache docs themselves are so stubbornly elusive in regard to what would seem like a common and obvious question: It's because the correct and complete answer is "It depends" ;)