Examine source code of Animated Pikachu Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Pikachu animated - dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(53, 53, 53, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(21, 21, 21)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(58, 58, 58)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(254, 241, 141, 0.73)",
      "popup": "rgb(21, 21, 21)",
      "popup_text": "rgb(254, 254, 254)",
      "button_background_hover": "rgba(80, 75, 41, 0.73)",
      "tab_selected": "rgb(46, 41, 23)",
      "tab_loading": "rgba(254, 241, 141, 0.73)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5c68a094-b028-4588-975e-357fd7dc50e0}"
    }
  }
}