Examine source code of Clean Copy

{
  "manifest_version": 2,
  "name": "Clean Copy",
  "version": "1.4.0",
  "description": "Cleans up URLs for easy sharing. No URL shorteners needed!",
  "icons": {
    "19": "images/icon19.png",
    "38": "images/icon38.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "clipboardWrite"
  ],
  "browser_action": {
    "default_icon": "images/icon48.png",
    "default_title": "Clean Copy",
    "default_popup": "popup/copy.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "darkrockstudios@gmail.com"
    }
  }
}