Before one spends a good deal of time converting the RFCs into a well formatted EPUB with modern, legible typography… one should read RFC COPYRIGHTS & IPR.
I learned a new language (the actual purpose of the exercise), and had a grand time with fuzzy algorithms for deriving the intent behind the sequence of bytes, but ultimately, I can share it with no one and will not finish it. (Sorry Mechanical Turk, you will not get to labor away on my edge cases.)
Long story short on the RFCs: It doesn’t appear that anyone thought out the copyright issues for many years and now it is too hard to resolve it.
Probably the best solution would be to find the 10% of RFCs that matter and build replacements with proper rights assignment and move on, or just live with them as is.