So it turns out that the last time the #HardenedBSD 16-CURRENT installer builder successfully built img/iso files was build 65 from 07 Dec 2025.
So that tells me two things: I need to check for the existence of specific files in our build script and throw an error when memstick.img and/or disc1.iso (and related) are missing for some reason.
I suspect I screwed something up when trying to drudge through this pkgbase stuff. Upstream made a freakton of rushed last-minute changes to the src build framework to support pkgbase and I wasn't able to properly keep up.