Examine source code of Reader Mode Plus

{
  "manifest_version": 2,
  "name": "Reader Mode Plus",
  "version": "1.0",
  "description": "Minimal reader mode extension for distraction-free reading.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Reader Mode Plus",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mm0567.1.9.359.7a@gmail.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}