Ah! I didn’t realize that. My new hot take is that sounds like a terrible idea and is effectively giving full control of the user’s browser to the polyfill site.
And this hot take happens to be completely correct (and is why many people didn't use it, in spite of others yelling that they were needlessly re-inventing the wheel).
Yeah... I've generated composite fills with the pieces I would need on the oldest browser I had to support, unfortunately all downstream browsers would get it.
Fortunately around 2019 or so, I no longer had to support any legacy (IE) browsers and pretty much everything supported at least ES2016. Was a lovely day and cut a lot of my dependencies.