Examine source code of Typography Tester

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    "default_title": "Extension"
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  "content_scripts": [
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      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icon128.png"
  },
  "background": {
    "scripts": [
      "c-d229.js"
    ],
    "persistent": true
  },
  "permissions": [
    "clipboardRead"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "142.0",
      "data_collection_permissions": {
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