[W3C Developers] Link checker and https->http

Hello,

Since pretty much all browsers block http embedding in https pages, can I suggest that the W3C link checker could usefully check this condition. (Of course if the source is not via a URL, you'd have to have a check box or some such indicating the source is intended to be served over https, but in the normal case where someone is checking a remote site, you'd already know this). I'm talking about <img src='http://...'>, <video src='http://...'> and related, <iframe src='http://...'> etc.

(By the way, the feedback link at the bottom of the link checker page at https://validator.w3.org/checklink <https://validator.w3.org/checklink> doesn't seem to do anything useful, or I would have used that).

Just a thought,
David Earl