What is the first argument to PackageLoader for in Python's jinja module

Okay so I have the following, I only want to know what "yourapplication" is. It's supposed to be a module, but a module that does what?

The website is down so there's currently no way I can look up how to instantiate a new Jinja based project

from jinja2 import Environment, PackageLoader
env = Environment(loader=PackageLoader('yourapplication'))

Thank you in advance!