Examine source code of QuickDefine

{
  "manifest_version": 2,
  "name": "QuickDefine",
  "version": "1.0",
  "description": "Look up word definitions with Ctrl + double-click.",
  "permissions": [
    "activeTab",
    "storage",
    "https://api.dictionaryapi.dev/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@quickdefine-extension",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icon.svg",
    "default_title": "QuickDefine"
  }
}