I approve of asking the customer to confirm the download.

I have a huge problem with the Chrome implementation: it fails silently. The only way to see what happened after you hammer a download link but your download does not start is to look at the dev console for logged browser errors!

That UX is terrible for customers dealing with legacy sites. It's even worse than the UX for dealing with self-signed certificates - surely an HTTPS site linking to an HTTP download deserves at least the same chance that a self-signed HTTPS site gets?