See example in the URL field.
The documentation is not 100% clear on what eiredirects= is supposed to do, but I believe it is supposed to return a list of pages that transclude a redirect to the eititle page (in this case, there are several redirects that provide aliases for [[Template:Category redirect]], including for example, [[Template:Categoryredirect]]). If these pages were being returned by the query, they would be in the results of the above link, between [[Category:Lavalers]] and [[Category:Media in New Mexico]], based on the page id for Template:Categoryredirect. As you can see, the query does not return these pages.
Another possible interpretation is that the query is supposed to return pages that are redirects to a title that transcludes [[Template:Category redirect]] (although I have no idea what the use case for this would be). Examining the results of the query (including pages before and after the one I've pasted in the URL field), however, indicates that no such pages are being returned, and there do not appear to be any <redirlinks> elements anywhere in the query response.