Geometry Dash Genesis is a fangame inspired by the popular rhythm-based platformer, Geometry Dash, which was originally created by RobTopGames. Fangames like Geometry Dash Genesis are often developed by enthusiastic fans who are inspired by the original game's mechanics and gameplay.
The note for Mac users you provided contains instructions on how to extract and run the game successfully on a Mac computer. It's common for macOS to require specific commands to bypass security features when running software from external sources to ensure the user's safety.
Geometry Dash and its fan-created versions like Geometry Dash Genesis continue to attract a dedicated community of players and level designers who enjoy the challenging and rhythmic gameplay that the series offers. These fan-created versions often add new levels, mechanics, and content to expand upon the original game's concept and keep the community engaged.