Examine source code of LookStuffUp

{
  "manifest_version": 2,
  "name": "LookStuffUp",
  "version": "1.2",
  "description": "Get instant context for selected text.",
  "permissions": [
    "storage",
    "https://www.googleapis.com/",
    "https://api.duckduckgo.com/",
    "https://*.wikipedia.org/",
    "https://*.wiktionary.org/",
    "https://api.dictionaryapi.dev/"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "styles.css"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "lookitup@vibhorsingh.com",
      "strict_min_version": "58.0"
    }
  }
}