Hi. I was surprised to see that ''mw.loadJsonData'' actually changes string keys like "90" in JSON to a numeric key 90 in Lua.
That makes accessing the Lua table harder. There was only one type of keys in JSON (i.e string), and it becomes 2 incompatible types in Lua (string or number) which causes a more complex code to handle the data.
I know it is too late to change ''mw.loadJsonData'' behaviour now, but at least you could add an option to it so that every key can be kept as a string.