Examine source code of vk emoji

{
  "name": "vk-emoji",
  "version": "3.0.1",
  "author": "zemf4you",
  "description": "Increases the resolution of stickers and emoji in the web version of VK.",
  "icons": {
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.vk.com/*"
      ],
      "js": [
        "src/index.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "vk-emoji",
    "default_icon": "icons/32.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{ac747232-679c-491a-9966-bd9319625ced}"
    }
  }
}