Examine source code of Yeah !

{
  "manifest_version": 3,
  "name": "Yeah !",
  "version": "1.1.0",
  "author": "Inklay",
  "description": "Miss the Miiverse ? Me too",
  "icons": {
    "128": "icon128.png"
  },
  "permissions": [
    "clipboardRead",
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "js": [
        "yeah.js"
      ],
      "css": [
        "yeah.css"
      ],
      "matches": [
        "https://x.com/*",
        "https://twitter.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "yeah@inklay.net"
    }
  }
}