Examine source code of Notebook-darker

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Notebook-darker",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(62, 59, 59)",
      "toolbar_text": "rgb(216, 206, 210)",
      "frame": "rgb(62, 59, 59)",
      "tab_background_text": "rgb(160, 147, 155)",
      "toolbar_field": "rgb(80, 75, 75)",
      "toolbar_field_text": "rgb(216, 206, 210)",
      "tab_line": "rgb(118, 146, 153)",
      "popup": "rgb(62, 59, 59)",
      "popup_text": "rgb(227, 219, 208)",
      "tab_loading": "rgb(118, 146, 153)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e0313ed1-5306-4665-8c9c-4394db3664f2}"
    }
  }
}