Examine source code of Yellowish

{
  "theme": {
    "images": {
      "theme_frame": "gradient-yellow-header.png"
    },
    "colors": {
      "frame": "#b18d00",
      "tab_background_text": "#171300"
    }
  },
  "version": "2.0",
  "name": "Yellowish",
  "manifest_version": 2,
  "description": "Simple yellow gradient Persona."
}