Examine source code of WhatsApp Direct

{
  "manifest_version": 2,
  "name": "WhatsApp Direct",
  "version": "1.0.0",
  "description": "Detects phone numbers on pages and lets you open chats directly in WhatsApp (web or app). Powered by wappdirect.pro.",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_title": "WhatsApp Direct",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "contextMenus",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/utils.js",
        "content/content.js"
      ],
      "css": [
        "content/content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "wappdirect@wappdirect.pro",
      "strict_min_version": "78.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}