But these links... where do they exist? In my experience they are produced from user INPUT. For example I click the sort button and sort by low to high and that

But these links... where do they exist? In my experience they are produced from user INPUT. For example I click the sort button and sort by low to high and that adds a &sort=asc. Now I have a new url. After the input. But a crawler just visits the page right? Its not selecting from dropdowns, checkboxes, etc. So apparently all combinations are pregenerated somewhere? That seems weird to me and why I was asking about their use case.