Examine source code of Easy XSS V2

{
  "manifest_version": 2,
  "name": "Easy XSS V2",
  "description": "__MSG_pluginDesc__",
  "version": "2.0",
  "default_locale": "en",
  "applications": {
    "gecko": {
      "strict_min_version": "56.0a1",
      "id": "{53480359-6111-4b3d-b4bd-9a7604ab4499}"
    }
  },
  "background": {
    "scripts": [
      "app.js"
    ]
  },
  "permissions": [
    "menus",
    "activeTab",
    "clipboardRead",
    "clipboardWrite"
  ]
}