Examine source code of YOUTUBE-RTL

{
  "manifest_version": 2,
  "name": "YOUTUBE-RTL",
  "version": "1.0.1",
  "description": "Re-renders YouTube pages in RTL mode for better text readability (supports only Arabic RTL characters).",
  "icons": {
    "48": "icons/rtl-48.png",
    "96": "icons/rtl-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "app.js"
      ]
    }
  ]
}