RxJS V5 official docs at http://reactivex.io/rxjs/manual/overview.html
These files are not meant for reading directly in GitHub, they are just source code for generating the official page. You should find the docs at http://reactivex.io/rxjs/manual/overview.html, containing all the documentation. Be aware, navigating to http://reactivex.io/rxjs will redirect you directly to the new V6 docs at https://rxjs-dev.firebaseapp.com.
EVERYTHING WITHIN THIS FOLDER IS RELATED TO RxJS 5 AND WILL NOT BE MAINTAINED. CHECK OUT THE NEW DOCS