What's model_name in PPOConfig in lab3?

in API, I found the doc says about model_name: “Name of model to use - used only for tracking purposes”.
I don’t understand how this model is used to do tracking, could anyone help me?

Its meant that you give the model a string name to be distinguished from other model!

So it is just a name, not some specific existing model, Right?
Thank you for your reply!