Cisco RegEx

I'm still a little green to Cisco RegEx. I know that ^ represents the beginning of a string and $ is the end, but does ^$ with nothing in the middle essentially mean anything?

Edit: Think I found my answer here, I just didn't know how to find it at first.

https://community.cisco.com/t5/other-collaboration-subjects/bgp-and-null-path-announcement/td-p/479687