Examine source code of Sentinels

{
  "name": "Sentinels",
  "manifest_version": 2,
  "version": "6.0",
  "theme": {
    "images": {
      "theme_frame": "ttest.png"
    },
    "colors": {
      "frame": "rgba(15, 15, 15, 1)",
      "tab_background_text": "rgba(181, 181, 181, 1)",
      "toolbar": "rgba(15, 15, 15, 1)",
      "bookmark_text": "rgba(181, 181, 181, 1)",
      "toolbar_field": "rgba(26, 26, 26, 1)",
      "toolbar_field_text": "rgba(181, 181, 181, 1)",
      "tab_line": "rgba(255, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{966370cc-9197-4ed8-950a-1f70fe0bdb74}"
    }
  }
}