PHP Question

I am just learning php, just kind of tinkering with it and learning as I go. I am editing my category.php page, as I want to make it have a different look to it. Here is the code:

<?php
					// Start the Loop.
					while ( have_posts() ) : the_post();

					/*
					 * Include the post format-specific template for the content. If you want to
					 * use this in a child theme, then include a file called called content-___.php
					 * (where ___ is the post format) and that will be used instead.
					 */
					get_template_part( 'content', get_post_format() );

					endwhile;
					// Previous/next page navigation.
					twentyfourteen_paging_nav();

				else :
					// If no content, include the "No posts found" template.
					get_template_part( 'content', 'none' );

				endif;
			?>

My question is regarding this line of code:
get_template_part( 'content', get_post_format() );
What php file is it hitting? Where are ‘content’ and get_post_format() ?
Once I know the .php file, I can edit it, and the results should be seen on my site (I think).

Thanks