Opensource.com - https://opensource.com/article/18/7/requests-for-comments-to-know
Reading the source is an important part of open source software. It means users have the ability to look at the code and see what it does.
But “read the source” doesn’t apply only to code. Understanding the standards the code implements can be just as important. These standards are codified in documents called “Requests for Comments” (RFCs) published by the Internet Engineering Task Force (IETF). Thousands of RFCs have been published over the years, so we collected a few that our contributors consider must-reads.