Examine source code of Hover Dictionary

{
  "manifest_version": 2,
  "name": "Hover Dictionary",
  "version": "1.0",
  "description": "Show word definitions on mouse hover.",
  "permissions": [
    "activeTab",
    "https://api.dictionaryapi.dev/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{7545c888-0c16-442d-aadf-a80f55c36504}"
    }
  }
}