Examine source code of Dictionary Everywhere

{
  "content_scripts" : [
    {
      "js" : [
        "content.js" 
      ],
      "matches" : [
        "<all_urls>" 
      ],
      "run_at" : "document_idle" 
    }
  ],
  "description" : "Double-click any word on a webpage to see its definition in a popup.",
  "manifest_version" : 2 ,
  "name" : "Dictionary Everywhere",
  "icons" : {
    "48" : "icons/icon-48.png",
    "96" : "icons/icon-96.png",
    "128" : "icons/icon-128.png"
  },
  "permissions" : [
    "https://en.wiktionary.org/*" 
  ],
  "version" : "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "dictionary-everywhere@stationaryaction.app",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "websiteContent"
        ]
      }
    }
  }
}