Examine source code of VK Messages Label Return

{
  "name": "VK Messages Label Return",
  "version": "1.0.1",
  "description": "This extension brings 'messages' instead of 'messenger' back on the vk.com",
  "manifest_version": 2,
  "icons": {
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "https://vk.com/*"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "https://vk.com/*"
  ]
}