Examine source code of WhatsApp Font Changer

{
  "manifest_version": 2,
  "name": "WhatsApp Font Changer Pro",
  "version": "1.2.0",
  "description": "Change WhatsApp Web font, size, weight and spacing with a clean Arabic interface.",
  "permissions": [
    "storage",
    "*://web.whatsapp.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://web.whatsapp.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_title": "WhatsApp Font Changer Pro",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "whatsapp-font-changer-arabic@local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}