Deployment of X-forwarder on all VIP

Thank you boneyard and Daniel_Wolf for your answers to my queries. I have another question. I found this knowledge-based article for verifying the X-Forwarded-For Header Inserted by the BIG-IP.

Using an irule to verify the X-Forwarded-For Header Inserted by the BIG-IP (f5.com)

My questions are as follows: 

1) Please explain the meaning of 10.10.10.10 in the script.

2) Is it possible to run the script written on the KB article and apply it to all 187 virtual servers at once without erasing the iRules that were previously configured on the above-mentioned virtual servers? The newly configured iRule overwrites the previously configured ones when I run the command below.

tmsh list ltm virtual one-line | grep "profiles.*\ http\ " | awk '{ print $3 }' | xargs -I vs_name tmsh modify ltm virtual vs_name rules { X-Forwarded-For-Verify }