piwik-checker/_locales/en/messages.json

{
  "extention_description": {
    "message": "[the description]",
    "description": "the short discription shown in the extention list"
  },
  "popup_text": {
    "message": "This page uses Piwik",
    "description": "text shown in popup when clicked on button in navigation bar"
  }
}