Nyan cat extension

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Nyan cat extension",
  "version": "1.0.2",
  "description": "Nyan cat in youtube bar extension",
  "icons": {
    "16": "assets/icon16.png",
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "author": "Bogdan Pryvalov",
  "web_accessible_resources": [
    {
      "resources": [
        "assets/rainbow.png",
        "assets/night-sky.gif",
        "assets/catty.gif",
        "assets/icon-nyan.png"
      ],
      "matches": [
        "https://*.youtube.com/*"
      ]
    }
  ],
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "host_permissions": [
    "https://*.youtube.com/*"
  ],
  "manifest_version": 3
}