Examine source code of Prevent New Tabs — Per-Site Popup Blocker

{
  "manifest_version": 2,
  "name": "Prevent New Tabs — Per-Site Popup Blocker",
  "version": "1.1.0",
  "description": "Stops annoying websites from opening new tabs/popups. Click the toolbar icon to turn it on for the site you're currently on — your choice is remembered per website, even after restarting the browser. Free plan covers 1 site; Pro unlocks unlimited sites.",
  "author": "",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "tabs",
    "webNavigation",
    "storage",
    "alarms",
    "<all_urls>",
    "https://api.keygen.sh/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "background": {
    "scripts": [
      "license.js",
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Prevent New Tabs",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "prevent-new-tabs@local.extension",
      "strict_min_version": "78.0",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo"
        ]
      }
    }
  }
}