Examine source code of Show Data Variables

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    "gecko": {
      "id": "var-show-data-variables@onii.com",
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      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
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    "storage",
    "activeTab",
    "<all_urls>"
  ],
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      "background.js"
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  },
  "sidebar_action": {
    "default_panel": "sidepanel.html",
    "browser_style": false,
    "default_title": "var - show data variables",
    "open_at_install": true
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "run_at": "document_start",
      "js": [
        "content-scripts/content.js"
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    }
  ],
  "browser_action": {}
}