Examine source code of Numix Blue (dark)

{
  "manifest_version": 2,
  "name": "Numix Blue (dark)",
  "description": "Numix background with some blue accents, optimized for use with dark OS themes",
  "version": "1.1",
  "author": "Dillinger",
  "homepage_url": "https://addons.thunderbird.net/en-US/thunderbird/user/dillinger/",
  "theme": {
    "colors": {
      "frame": "#2d2d2d",
      "tab_background_text": "#f9f9f9",
      "tab_line": "#42a5f5",
      "tab_loading": "#42a5f5",
      "toolbar_field": "#2d2d2d",
      "toolbar_field_text": "#f9f9f9",
      "toolbar_field_border": "#68696A",
      "toolbar_bottom_separator": "#26262a",
      "toolbar": "#404043",
      "bookmark_text": "#f9f9f9",
      "button_background_hover": "#ffffff40",
      "button_background_active": "#ffffff66",
      "popup": "#404043",
      "popup_text": "#f9f9f9",
      "ntp_text": "#f9f9f9",
      "ntp_background": "#2d2d2d",
      "sidebar": "#38383D",
      "sidebar_text": "#f9f9f9",
      "sidebar_border": "#26262a"
    }
  },
  "applications": {
    "gecko": {
      "id": "numix-blue-dark@dillinger",
      "strict_min_version": "68.0"
    }
  },
  "icons": {
    "32": "numix-blue-icon.png"
  }
}