Examine source code of Deep Dark Adwaita

{
  "name": "Deep Dark Adwaita",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "black.jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(142, 142, 142, 1)",
      "toolbar": "rgba(36, 36, 36, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 0, 0, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(36, 36, 36, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eb7ebd89-10b2-4c47-b4b1-8e7dbbc8804c}"
    }
  }
}