Examine source code of Focus Reader

{
  "manifest_version": 2,
  "name": "Focus Reader",
  "version": "0.2.5",
  "description": "Stay focused while reading articles one sentence, image, or list item at a time.",
  "icons": {
    "16": "icons/focus-reader-16.png",
    "32": "icons/focus-reader-32.png",
    "48": "icons/focus-reader-48.png",
    "96": "icons/focus-reader-96.png",
    "128": "icons/focus-reader-128.png"
  },
  "permissions": [
    "activeTab",
    "menus",
    "storage"
  ],
  "background": {
    "scripts": [
      "extension-api.js",
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Choose a Focus Reader mode",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/focus-reader-16.png",
      "32": "icons/focus-reader-32.png"
    }
  },
  "commands": {
    "focus-current-page": {
      "suggested_key": {
        "default": "Ctrl+Shift+F"
      },
      "description": "Open the current article in the last used Focus Reader mode"
    }
  },
  "web_accessible_resources": [
    "reader.html",
    "reader.css",
    "reader.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "focus-reader@msvos.local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}