Tried building with some other arguments/configs, went from 1,2M on X11 to 664K, which seems to place it under Lynx (text-only, 714k) but above OffByOne (full HTML 3.2, 409k). Of course, my experiment barely implements anything from a "real" browser, so unfair comparison really.
Neat collection of apps nonetheless, some really impressive stuff in there.
https://tinyapps.org/network.html
Of course, "AI-generated browser is 1MB" is neither here nor there.