Examine source code of ILovePDF 2

{
  "manifest_version": 3,
  "name": "ilovepdf",
  "version": "1.3",
  "description": "I Love PDF 2 is a free  for merge, split, compress and convert your files.",
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "support@ilovepdf2.com",
      "strict_min_version": "123.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}