Is there a way for links to make suggestions to browsers? Specifically, I would like to see links that can provide an md5 or other hashes to a browser so that it can automatically check for corrupt files. Also, if the syntax is flexible enough, a link could suggest alternate sites if the primary site is down or too slow. I'm sure that there could be many other uses for this, including custom key value pairs for custom plugins.
Here is a sample tag syntax that shows the general idea:
<a href="download.com/file.exe" custom="md5:2442349232; sh1:4000384320; mirror:bestdownloads.com/file.exe"> download </a>