Examine source code of InstaPDFPro

{
  "manifest_version": 3,
  "name": "InstaPDFPro",
  "description": "Easily convert documents to PDF.",
  "version": "2.6",
  "icons": {
    "16": "instaicon16.png",
    "48": "instaicon48.png",
    "128": "instaicon128.png"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "instapdfpro@example.com"
    }
  }
}