cURL downloads whatever the server gives you based on your request (that's probably a gross simplification but in this context it's probably good enough). Generally, if you request a webpage, you'll get the same data that your browser would get (often colloquially called HTML).
From some basic searching online, it doesn't look like GameTracker has a public API for getting data from it but there was mention of a "feed" available for premium members. See
this thread.
Also, I found some
python code that appears to grab the HTML and seeks out the data in the HTML.