Examine source code of Beautiful White Dark

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{c456a7d2-d6d8-49e1-b8a9-7d616fbd67cf}"
    }
  },
  "version": "2.5",
  "name": "Beautiful White Dark",
  "author": "GODIE",
  "description": "Tema Claro y Oscuro para Firefox.",
  "icons": {
    "32": "icon-32.png"
  },
  "theme": {
    "properties": {
      "color_scheme": "dark",
      "content_color_scheme": "dark"
    },
    "colors": {
      "frame": "#222831",
      "tab_background_text": "#bbbbbb",
      "frame_inactive": "#343d4b",
      "toolbar": "#ebebeb",
      "toolbar_field": "#efefef",
      "toolbar_field_text": "#303030",
      "toolbar_top_separator": "#202020",
      "toolbar_bottom_separator": "#cccccc",
      "bookmark_text": "#3a3a3a",
      "toolbar_field_border": "#b3b3b3",
      "toolbar_field_focus": "#dadada",
      "toolbar_field_border_focus": "#5080d0",
      "toolbar_field_highlight": "#5e60ff",
      "toolbar_field_highlight_text": "#fafafa",
      "toolbar_field_text_focus": "#252525",
      "toolbar_vertical_separator": "#cccccc",
      "button_background_hover": "#bdc2c2",
      "button_background_active": "#a2a9a9",
      "icons": "#4f4f4f",
      "icons_attention": "#0a84ff",
      "ntp_background": "#1c222b",
      "ntp_text": "#ffffff",
      "ntp_card_background": "#2a3039",
      "popup": "#222831FD",
      "popup_text": "#CCCCCC",
      "popup_border": "#5a5a5a80",
      "popup_highlight": "#4e50ff",
      "sidebar": "#292f38",
      "sidebar_text": "#eaeaea",
      "sidebar_border": "#434b56",
      "sidebar_highlight": "#202124",
      "sidebar_highlight_text": "#eaeaea",
      "tab_line": "#22283100",
      "tab_loading": "#252525",
      "tab_loading_inactive": "#252525",
      "tab_selected": "#ebebeb",
      "tab_background_separator": "#777777",
      "tab_text": "#283148"
    }
  }
}