Route Filters are a new system in XenForo 1.2 to allow you to change the standard URLs generated by XenForo, including any URLs generated by add-ons.
It's a fairly simple system to show, but it's very powerful with a little thought. Let's look at what you can set with it:
Other than a list of route filters, that's really it for the system. So how about a few examples...
Changing a route prefix
There's an add-on that does this right now, but we can do it simply from here. For example, if you want to change the resources URL to downloads, you'd just enter resources/ in the find box and downloads/ in the replace box.
Instantly, any links to http://xenforo.com/community/resources/ would become...