Examine source code of Castrol 60

{
  "name": "Castrol 60",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "Castrol 601.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(247, 247, 247, 1)"
    }
  }
}