Examine source code of Instagram Unfollowers

{
  "manifest_version": 2,
  "name": "Instagram Unfollowers",
  "version": "1.0",
  "description": "Find out who doesn't follow you back on Instagram",
  "permissions": [
    "activeTab",
    "storage",
    "*://*.instagram.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{644157b0-0bf9-4dc4-aa71-037387399f13}"
    }
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon48.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.instagram.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icons/icon48.png"
  }
}