Is there an IP variable? What file is it stored in?

I see in the FAQ Piwik tracked the client’s IP. I can’t seem to find it in any of the files? I’m looking for the PHP variable.

See this faq: How to - Analytics Platform - Matomo

I’m not really trying to get it from the db. I’m looking for the PHP associated in storing it. where is the $_SERVER[‘REMOTE_ADDR’]?