Examine source code of angels descent

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "angels descent",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(255, 0, 0)",
      "frame": "rgb(41, 0, 0)",
      "tab_background_text": "rgb(255, 221, 109)",
      "toolbar_field": "rgb(75, 5, 0)",
      "toolbar_field_text": "rgb(255, 0, 4)",
      "tab_line": "rgb(255, 0, 0)",
      "popup": "rgb(69, 0, 0)",
      "popup_text": "rgb(255, 246, 155)",
      "button_background_active": "rgb(193, 156, 34)",
      "button_background_hover": "rgb(41, 0, 0)",
      "frame_inactive": "rgb(109, 33, 33)",
      "icons_attention": "rgb(75, 5, 0)",
      "icons": "rgb(255, 246, 155)",
      "ntp_background": "rgb(75, 5, 0)",
      "ntp_text": "rgb(255, 221, 109)",
      "popup_border": "rgb(255, 221, 109)",
      "popup_highlight_text": "rgb(255, 244, 208)",
      "popup_highlight": "rgb(255, 0, 0)",
      "sidebar_border": "rgb(255, 221, 109)",
      "sidebar_highlight_text": "rgb(255, 0, 0)",
      "sidebar_highlight": "rgb(255, 0, 0)",
      "sidebar_text": "rgb(193, 156, 34)",
      "sidebar": "rgb(75, 5, 0)",
      "tab_background_separator": "rgb(109, 33, 33)",
      "tab_loading": "rgb(193, 156, 34)",
      "tab_selected": "rgb(75, 5, 0)",
      "tab_text": "rgb(255, 221, 109)",
      "toolbar_bottom_separator": "rgb(255, 221, 109)",
      "toolbar_field_border": "rgb(255, 221, 109)",
      "toolbar_field_highlight": "rgb(255, 244, 208)",
      "toolbar_top_separator": "rgb(255, 221, 109)",
      "toolbar_vertical_separator": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{76e5be36-6f2a-4e63-9f31-764e58635c2c}"
    }
  }
}