Examine source code of Mario 3

{
  "theme": {
    "images": {
      "theme_frame": "marioheader.png"
    },
    "colors": {
      "frame": "#4d4d4d",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Mario 3",
  "manifest_version": 2,
  "description": "Classic mario 3 level design"
}