Solarus is a free and open-source game engine, licensed under GPL v3. It is written from scratch in C++ and uses SDL2 (it's not an emulator). Development began in 2006. The goal of the engine is to allow people to create their own Action-RPG games (also called Zelda-like games). It is totally independent from Nintendo.
Solarus will require game data like zsdx.
Optional Dependency
qt5 is an optional dependency for the GUI frontend.
qt5 is *required* if you are going to build solarus-quest-editor.