Crumpler

I was cleaning today and came across a potential problem.
I have not found much on parking brake cables in previous threads or my WSM.

I wasn't overly concerned about the boot falling apart in my hand but that snarl I'm holding on the passenger side appears to be the lining around the cable that has been pulling on the guide tube?

Can somebody orient me and maybe explain mechanics of the problem?
Common Failure Point?
Brake works fine, BTW.
Thanks.