RFCs in the wild
Collection: https://awesomeopensource.com/projects/rfc
HTTP (protocol), HTTP Core: https://httpwg.org/http-core/
Rust (programming language, runtime & SDK), The Rust RFC Book: http://rust-lang.github.io/rfcs/introduction.html
Switft (programming language), Swift Evolution: https://apple.github.io/swift-evolution/
F# (programming language), fsharp/fslang-design: https://github.com/fsharp/fslang-design
C# (programming language), dotnet/csharplang: https://github.com/dotnet/csharplang
.NET (runtime & SDK), dotnet/designs: https://github.com/dotnet/designs
Ember.js (web framework), Ember RFCs: https://emberjs.github.io/rfcs/introduction.html
React.js (web framework), React RFCs: https://github.com/reactjs/rfcs
React Native (GUI framework), react-native-community/discussions-and-proposals: https://github.com/react-native-community/discussions-and-proposals