Understanding IRule with Proxypass datagroup

Trying to understand a existing config,

I see that with in a datagroup, below example 

string is abc.myc.com

value is xyz.it.myc.com my-pool-name

just trying to understand what does value mean here.

my understanding is as soon as abc.myc.com is hit it will go to my-pool-name . Just want to know what  is  xyz.it.myc.com ? 

Thanks for your help