Examine source code of Custom Mandlebrot

{
  "theme": {
    "images": {
      "theme_frame": "Persona.HEADER.Mandlebrot.2.png"
    },
    "colors": {
      "frame": "#524f4f",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Custom Mandlebrot",
  "manifest_version": 2,
  "description": "N/A"
}