R2 is a L3 packet router written in rust inspired by the design of VPP https://fd.io. It potentially will evolve into an L4/L7 proxy (yet another!)
NOTE: R2 compiles and works only on linux as of now, tested with Ubuntu 20.04, although it should work with any later ubuntu also
The recommended method is to first go through the general overview page https://gopakumarce.github.io/R2/, which has links with a high level overview of R2. And once that is done, go through the TryMe page https://gopakumarce.github.io/R2/tryme/ and just get familiar with downloading the code, compiling it and getting R2 running with a simple two container setup. Once that is done you can refer to the code itself accompanied by the documentation in various modules of the code
NOTE: The contents in the links mentioned above are also present in the Docs/content/en directory here