Examine source code of Fixed Text Copier

{
  "manifest_version": 3,
  "name": "Fixed Text Copier",
  "version": "1.0",
  "description": "Copy fixed text for Gmail with a single click.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "yannellih7041987udttv@hotmail.com"
    }
  },
  "permissions": [
    "clipboardWrite"
  ]
}