spam checker (1 1)

I’ve been looking through the php to find a solution but I figured I’d ask here before making big changes to the code…
I wanted to change the form so that when the user is answering the “1+1” question, instead of saying the question in that box it explains what that box is for. I.e. on the left it says the math question to be answered and the placeholder text in the actual answer box says “spam checker” or “making sure you are human”

Does that make sense?
I thought I had found the correct snippit in the php file in line 657 but that only changed the response in the settings area of my dashboard. Would love to know exactly which line or snippit in the php produces the placeholder value in the actual form.
Thanks.

https://www.ads-software.com/extend/plugins/contact-coldform/