Meredith Whittaker is not a techie AFAIK. Either way, I'd just like to know more about the thought process going into Signal's product and engineering decisions. The Signal team seems extraordinarily tight-lipped and that doesn't exactly inspire trust from where I stand.

Have you heard her speak? She seems pretty bright to me.

Their blog has (or had?) some extensive technical explanations, for example about their implemenation of features utilizing SGX.