Some games use "obfuscation." Developers intentionally scramble the variable names (e.g., global.v1 , global.v2 ) and remove string references to make reverse engineering harder. There is no fix for this; you simply have to deduce what the variables do by context.
The primary tool in the modern era is . While originally designed for the engine's most famous export, it has evolved into a Swiss Army Knife for GameMaker Studio 2 games. gamemaker studio 2 decompiler