Originally explored in simonw/datasette-notebook#2 (comment) - I wanted an efficient way to scan a list of URLs and figure out which if any of those corresponded to Datasette tables, canned queries or SQL output that could be represented as a table on a page.

It looks like a neat way to do that is with Link: header like this:

Link: http://127.0.0.1:8058/fixtures/compound_three_primary_keys.json; rel="alternate"; type="application/datasette+json"

I can put a <link href=... in the page header too.