TLDR pages is described as 'The TLDR pages are a community effort to simplify the beloved man pages with practical examples' and is an app in the OS & Utilities category. There are nine alternatives to TLDR pages for a variety of platforms, including Linux, Online / Web-based, Mac, Windows and Android. The best alternative is explainshell, which is both free and Open Source. Other great apps like TLDR pages are cheat.sh (Free, Open Source), Devhints (Free, Open Source), cheat (Free, Open Source) and Linux man-pages (Free, Open Source).
Cheat allows you to create and view interactive cheatsheets on the command-line. It was designed to help remind *nix system administrators of options for commands that they use frequently, but not frequently enough to remember.