Examine source code of Kittens at Play

{
  "name": "Kittens at Play",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(158, 104, 43, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(158, 108, 43, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(158, 108, 43, 0.12)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fea47879-929c-4438-8ad6-168edeaff251}"
    }
  }
}