I mostly focused on the cryptographic parts of the files. Here's what I wrote after the first details of cryptographic attacks were released: https://blog.cryptographyengineering.com/2013/09/06/on-nsa/

What I learned in that revelation was that the NSA was deliberately tampering with the design of products and standards to make them more vulnerable to NOBUS decryption. This surprised everyone I knew at the time, because we (perhaps naively) thought this was out of bounds. Google "SIGINT Enabling" and "Bullrun".

But there were many other revelations demonstrating large scale surveillance. One we saw involved monitoring the Google infra by tapping inter-DC fiber connections after SSL was added. Google MUSCULAR, or "SSL added and removed here". We also saw projects to tap unencrypted messaging services and read every message sent. This was "surprising" because it was indiscriminate and large-scale. No doubt these projects (over a decade old) have accelerated in the meantime.