I did not see anything in the screenshots that would inform the user of the add-on about backlinks, i.e. links to the current page from other sites.

A well-designed comprehensive link-checker. Thank you.

Your advertising doesn't do it justice - you don't show how it colours the links on the Web page being checked as it proceeds (thinking it didn't do this, I nearly didn't bother to download it).

It's not clear how to control it - e.g. how to abort. While it was still checking a page with 981 links (including numerous non-html documents), I fixed the page and opened it in a new tab (to keep the display of the old page), and when I started link checker on the newly fixed page, it continued recolouring both in sync with each other. If you didn't host the support page on facebook (which is inaccessible to those like me who are deliberately not facebook members) I could have asked these questions.