Examine source code of Copy Text Exclude

{
  "manifest_version": 2,
  "name": "Copy Text Exclude",
  "version": "1.0.0",
  "description": "Copy text from webpages while excluding selected portions",
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "copy-text-exclude@example.com",
      "strict_min_version": "58.0"
    }
  },
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  }
}