Hi @qqilihq,
if the sitemap finder, which uses a robots.txt only, does not find one, I’d like to propose trying “/sitemap.xml” as a fallback.
Also, I happen to notice regularly that servers are configured poorly, responding with a non 404 so you might consider adding a check if the retrieved document is of the XML-type and maybe the status quo too.
The url I provided as a string didn’t had a protocol present. You might consider being more strict about URLs.
Overall however, a really nice quality of life improvement! Thanks for the treat 
Best
Mike
