The Godot editor is a Godot game The Godot editor runs on the game engine. It uses the engine's own UI system, it can hot-reload code and scenes when you test your projects, or run game code in the editor. This means you can use the same code and scenes for your games, or build plugins and extend the editor. This leads to a reliable and flexible UI system, as it powers the editor itself. With the @tool annotation, you can run any game code in the editor.
https://cdn.masto.host/mastodongamedevplace/media_attachments/files/113/809/503/101/724/796/original/d185e6021147de8e.png