Resource Fork Files

This isn't necessarily a question specific to BetterZip, but I can't find a good answer anywhere else, and BetterZip is what alerted me to the presence of these files in the first place. I've noticed that in many ZIP archives, particularly ones that contain applications, there are several invisible resource fork folders (_MACOSX, for instance). As I understand it, these resource forks hold certain information about files. What I'm wondering is if it makes any difference whether or not I extract these with the file(s) in the archive. Do they hold information about the files in the archive or the archive itself? Thanks for any clarification on this.