[aur-general] What is pkgrel and why/how should I use it?

[karx via aur-general]

Hello all, sorry if this is not in the appropriate mailing list. I am
developing an AUR package, and it says that pkgrel is a required field.
Right now, I simply leave it at 1, but I want to know how I should really
use it and what its purpose is.

Thanks, Yash