[ehnto]

This is my only gripe. Please work with a spec first, so that the feature flows naturally through to other vendors. Especially because it's changing the way URLs work.

You're going to get people generating millions of these links around the web. That's a long term legacy of hyperlinks generated by the citizens of the web. Although the fallback is obviously pretty harmless, what about a future feature? If this doesn't work out, but some other feature down the line does, suddenly thousands of these links start working in weird ways. Or worse, the feature doesn't happen at all, because of the legacy of broken links. I know that's pessimistic, but URLs are the foundation of the web, changing how they work should be funneled through the spec.