Examine source code of dark mode

{
  "name": "dark mode",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "1646675103298.png"
    },
    "colors": {
      "frame": "rgba(23, 19, 19, 1)",
      "tab_background_text": "rgba(19, 247, 164, 1)",
      "toolbar": "rgba(46, 46, 38, 1)",
      "bookmark_text": "rgba(214, 195, 21, 1)",
      "toolbar_field": "rgba(0, 0, 0, 1)",
      "toolbar_field_text": "rgba(208, 255, 0, 1)",
      "tab_line": "rgba(47, 207, 29, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{705825b4-7111-4db8-ac9b-7ad388f2c63b}"
    }
  }
}