Reasonable possibility nobody involved signed an NDA or filled out any paperwork, given how unofficial it was. It's been fifteen years, it's likely the hardware in question is long deprecated in favor of covert hardware that looks like a modern smartphone or something.

Right, someone walking around carrying an iPod has gone from notable to mundane and back to notable. No longer the way to blend in.

It's also possibly one of the reasons we're so worried about Huawei here in the US right now: We know what our guys can do. We may know a fair bit about what China can or has done. And nobody wants to talk specifically about what those things are.

I remember a couple years ago hearing a talk about using smartphone camera sensors to detect radiation levels - the idea of using such devices is out in the open now

Using traditional film is more or less how radioactivity was discovered in the first place:

https://www2.lbl.gov/abc/wallchart/chapters/03/4.html

Using modern sensors seems like the logical extension of that.