Examine source code of Copy Word Counter

{
  "manifest_version": 2,
  "name": "Copy Word Counter",
  "version": "1.0",
  "description": "Hiển thị số từ vừa copy.",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_title": "Copy Word Counter"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{634f295d-196a-487d-8577-47b9a899f8fe}"
    }
  }
}