Examine source code of Krusty is after you

{
  "name": "Bad bad Krusty",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "krusty-4.png"
    },
    "colors": {
      "frame": "rgba(158, 158, 158, 1)",
      "tab_background_text": "rgba(3, 3, 3, 1)",
      "toolbar": "rgba(255, 255, 255, 0)",
      "bookmark_text": "rgba(235, 235, 235, 1)",
      "toolbar_field": "rgba(3, 3, 3, 0)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(208, 255, 0, 0.48)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{faea87db-83ef-4878-aaf3-6af1d30b6598}"
    }
  }
}