https://docs.godotengine.org/en/stable/tutorials/scripting/gdscript/gdscript_exports.html
GDScript exported properties — Godot Engine (stable) documentation in English
In Godot, class members can be exported. This means their value gets saved along with the resource (such as the scene) they're attached to, and get transferred...
gdscript exported propertiesgodot enginestabledocumentationenglish