Examine source code of Minimal Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Darkwall",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(34, 34, 34)",
      "toolbar_text": "rgb(238, 238, 238)",
      "frame": "rgb(34, 34, 34)",
      "tab_background_text": "rgb(238, 238, 238)",
      "toolbar_field": "rgb(34, 34, 34)",
      "toolbar_field_text": "rgb(238, 238, 238)",
      "tab_line": "rgb(238, 238, 238)",
      "popup": "rgb(34, 34, 34)",
      "popup_text": "rgb(238, 238, 238)",
      "frame_inactive": "rgb(238, 238, 238)",
      "tab_loading": "rgb(238, 238, 238)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9255d6de-b51e-46c1-883c-02a6d824c34e}"
    }
  }
}