Examine source code of Hold VK Sidebar

{
  "manifest_version": 2,
  "name": "hold-vk-sidebar",
  "version": "2.2",
  "content_scripts": [
    {
      "matches": [
        "https://vk.com/*"
      ],
      "css": [
        "hold-vk-sidebar.css"
      ]
    }
  ]
}