Examine source code of Faxmail

{
  "name": "Faxmail",
  "version": "1.0.1",
  "description": "A Chrome extension for Faxmail to help create temporary emails",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "fax@mailer-1234-abcd-5678-ef90-123456789abc",
      "strict_min_version": "42.0"
    }
  },
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Faxmail",
    "default_icon": "icon.png"
  },
  "permissions": [
    "storage",
    "clipboardRead",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "contentScript.css"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "asset.png",
        "icon.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}