Examine source code of web-lol

{
  "manifest_version": 2,
  "name": "Lol",
  "version": "1.0.1",
  "description": "Improve the browsing experience with happiness",
  "icons": {
    "48": "lol-web-48.png",
    "96": "lol-web-96.png"
  },
  "content_scripts": [
    {
      "css": [
        "style.css"
      ],
      "matches": [
        "https://*/"
      ]
    }
  ]
}