Examine source code of I feel good

{
  "theme": {
    "images": {
      "theme_frame": "persona-good-1.jpg"
    },
    "colors": {
      "frame": "#121111",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "I feel good",
  "manifest_version": 2,
  "description": "Katze Kater Maine-Coon I-feel-good good feeling Cat"
}