Here's the Tech Specs page, which is slightly more hidden: https://www.apple.com/iphone-duo/specs/

Notably, the inner screen has a nano‑texture finish (which Apple normally upcharges significantly for), which implies it is glass.

Very strange how in the middle of a specs page for the device they a pitch there suggesting you get an Apple Card (formatted on the spec page as if it was actually a spec of this device) before continuing on with the rest of the specs/features.

I haven't looked, but am guessing the probably exists on other Apple specs pages.

in the keynote they explicitly said it was a polymer. Apple materials technology is really good, but it's not "folding glass" good.