From searching the forum, this appears to be related to the new announcements feature, which I have not tried to implement for our site. I am assuming there is some code being inserted into my site to support this feature, but I have not done anything in the settings for this site for years. While it does not seem to affect my site in any way, I would like to avoid the notifications I regularly receive that I have a broken link for my site and then check the report only to find it is this every time.
OK, so how do I remove the link? Theoretically, broken links can affect a site’s Google ranking. I need to have the site checked for broken links because virtually all the posts have a link to an article somewhere else, and I waste time accessing the report only to discover that it is, once again, this webmentions link. Should I submit a bug report?
The spec appears to say that only POST requests should be sent to this URL, but it appears that your link check is following the URL and sending a GET request to it, which Ghost doesn’t need to support.
If I’m reading things correctly, this is a bug in how the link checker handles linked to webmentions specifically.