Page Embedding

I just moved a website built another person. Some of the webpages have embedded pages that reside within the same website. I am having issues with the embedded code since I am not familiar with it, as follows.

[my_content2 id=”134″ title=true /]

My initial thought was that the code was tied to a plugg-in but it does not seem so since there is no plugg-in that seem associated.

If someone can explain how the above code works or what it works with, it sure would be appreciated.