Thanks for the swift answer. I've been scanning my big board with various SEO tools and I've found found that XFMG, AMS, UBS and RMS attract a lot of dead links over time. Much more than forum. Which makes sense because articles and blogs often contain many off site links and images.
I understand. As I remember, some time ago you have also requested link checker for resource manager, which we have created and released - https://xenforo.com/community/resources/link-checker-for-resource-manager-by-addonslab.6115/ and there has been no sales for this add-on, not even from your side. So we are not much interested in putting so much effort to support additional content checkers if no one is going to use it.
If you are interested in these features feel free to open a ticket at https://customers.addonslab.com/submitticket.php and we will provide the terms to develop them for you.