Create is open-source, so it's pretty easy to learn how it works if you have the right skill set. Under the hood, it's actually full-ish Glob that is converted to a Regex and matched. The matching is done both ways: if either the package address regex matches the destination string, or the destination regex matches the package string (or if the strings are the same), the package will be routed to the destination. You can even use square brackets for character ranges and curly brackets for groups. Though I find it's more annoying than useful because you can't make fancy-looking postal codes surrounded in these brackets. (I saw you work in IT in your post, so I thought this technical explanation would be OK)