Examine source code of Password Field Reveal

{
  "manifest_version": 2,
  "name": "Password Reveal",
  "version": "1.0",
  "description": "Permanently reveals all password fields",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "reveal.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "password-reveal@local",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}