I'm using Godot to make it. In the engine, there're tons of UI nodes that help me to create a project like this. For me, what I have to know is to know the process of making a game with Love2D, and based on that I list down what I need to automate. That's how I came up with the idea of making this editor. On technical side, all you need to know is how the UI nodes work in Godot, and how to access to more low-level side, or the back-end such as running custom script, auto running the command, save the data file or writing a custom file.
Hope this anwser satisfy your question! Thank you very much for trying it out, I really appreciate it!