Examine source code of Night Owl

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Night Owl (sdras) for Firefox",
  "theme": {
    "colors": {
      "button_background_active": "#303b44",
      "button_background_hover": "#1d2c38",
      "icons": "#c5c5c5",
      "icons_attention": "#7e57c2cc",
      "bookmark_text": "#5f7e97",
      "popup": "#021320",
      "popup_text": "#d6deeb",
      "popup_border": "#021320",
      "popup_highlight": "#011627",
      "popup_highlight_text": "#ffffff",
      "ntp_background": "#011627",
      "ntp_text": "#8BADC1",
      "ntp_card_background": "#021320",
      "sidebar": "#001122",
      "sidebar_border": "#102a44",
      "sidebar_highlight": "#234d708c",
      "sidebar_highlight_text": "#ffffff",
      "sidebar_text": "#8BADC1",
      "frame": "#001122",
      "frame_inactive": "#010e1a",
      "tab_background_text": "#5f7e97",
      "tab_line": "#272b3b",
      "tab_loading": "#0e70c0",
      "tab_selected": "#0b2942",
      "tab_text": "#d2dee7",
      "toolbar": "#001122",
      "toolbar_top_separator": "#262A39",
      "toolbar_vertical_separator": "#122d42",
      "toolbar_bottom_separator": "#262A39",
      "toolbar_field": "#011627",
      "toolbar_field_focus": "#001122",
      "toolbar_field_border": "#011627",
      "toolbar_field_border_focus": "#001122",
      "toolbar_field_highlight": "#4373c2",
      "toolbar_field_highlight_text": "#d9e3f3",
      "toolbar_field_text": "#ced3d8",
      "toolbar_field_text_focus": "#ced3d8"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2b0ea4c5-0684-4417-b160-9c5df21e051a}"
    }
  }
}