Thanks. Someone had done a scan for security.txt files before but were unable to scan the entire Alexa Top 1 million websites. Only the top 1,000. I checked the top 1 million from a 1.5Mbit residential DSL line using Go routines.
The blog post has more details and a short overview of the results. It's linked at the bottom of the repo. I was hoping to get feedback on the code.