Examine source code of Dictionary.com Lookup

{
  "manifest_version": 2,
  "name": "Dictionary Lookup",
  "version": "1.0.3",
  "description": "Right-click any selected word to look it up on Dictionary.com.",
  "homepage_url": "https://www.dictionary.com",
  "author": "Richard Bottiglieri",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "96": "icons/icon96.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c2119714-823e-40c9-97cf-64cdce247b96}",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}