Examine source code of Dark Mode

{
  "name": "Dark Mode",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Leiste.png"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(0, 0, 0, 1)",
      "bookmark_text": "rgba(102, 102, 102, 1)",
      "toolbar_field": "rgba(51, 51, 51, 1)",
      "toolbar_field_text": "rgba(102, 102, 102, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c63f6edb-6cd3-44dc-a9c7-d3f8f4f6941c}"
    }
  }
}