I had a random theory the other day; we shall remember that they don't use their own chips and it's not an open source project either, unlike most projects we're used to around here. We're used to getting concise clear answers on all of our questions, but when you're working with big companies and NDAs, stuff gets tricky. It's possible that e.g. they have a license for the chip, but not for 'the asicboost', or something like that. Or maybe they got a spec of the chip (under NDA) that doesn't include everything (like asicboost information / how to use or activate it).
Just a theory
But it seems to me that we don't achieve anything by pressing further on this. Who knows; maybe the community will release a patch that adds the two bytes which change the string output format..