The feed URL for the search isn't contained on the page. Clicking 'Create RSS' makes a call to the server to store the search terms and returns a feed with a new rss_guid
. If there isn't an API to call you would need to examine the JavaScript and simulate a browser clicking on that button.
(As an implementation detail, the site returns different guid
s even when the search is the same, which implies that each 'Create RSS' is creating a new resource.)