Examine source code of Readability Toggle

{
  "manifest_version": 2,
  "name": "Readability Toggle",
  "version": "1.0.1",
  "description": "Toggle a lightweight readability mode for the current page.",
  "browser_specific_settings": {
    "gecko": {
      "id": "readability-toggle@example.com",
      "strict_min_version": "78.0"
    }
  },
  "icons": {
    "48": "icon.svg"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.svg"
  }
}