Examine source code of Steam Deck

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Steam Deck",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(42, 50, 66)",
      "toolbar_text": "rgb(221, 221, 221)",
      "frame": "rgb(21, 28, 37)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(221, 221, 221)",
      "toolbar_field_text": "rgb(0, 120, 215)",
      "tab_line": "rgba(0, 120, 215, 0.4)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 120, 215)",
      "tab_loading": "rgba(0, 120, 215, 0.4)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f8f4bea2-dfc7-4622-929d-9c39fe50340e}"
    }
  }
}