Examine source code of Simple

{
  "manifest_version" : 2 ,
  "version" : "1.0",
  "name" : "Simple",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-017-2de428a06dc9ef685439af2292aab531.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(239, 241, 232)",
      "toolbar_text": "rgb(14, 14, 14)",
      "frame": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(14, 14, 14)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(14, 14, 14)",
      "tab_line": "rgb(14, 14, 14)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(14, 14, 14)",
      "tab_loading": "rgb(14, 14, 14)"
    }
  }
}