Logstash included grok patterns dir?

I'm running logstash 2.3 on a CentOS 6 installation. I used the Elasticsearch yum repo to install logstash.

My question is where in Linux are the included grok pattern files stored? I looked in /opt/logstash but couldn't find it there.

You can watch patterns here :

And if really you want to access patterns in your local installation, search here :