Examine source code of Permareader

{
  "manifest_version": 2,
  "name": "Permareader",
  "version": "1.0",
  "description": "Enables or disables Firefox's built-in Reader Mode globally - no more pointless toggling.",
  "icons": {
    "48": "icons/out48.jpg",
    "96": "icons/out96.jpg"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "permareader@troyrennie.ca"
    }
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/out48.jpg",
      "96": "icons/out96.jpg"
    },
    "default_title": "Permareader: Toggle"
  },
  "background": {
    "scripts": [
      "permareader-bg.js"
    ]
  }
}