Chrome 42 for Windows, Mac, and Linux users that now lets websites send you alerts, no matter your browser is open or not. The latest version of Chrome comes with fixes for 45 security vulnerabilities in the web browser. Google paid out more than $21,000 bounties to external researchers who contributed bugs fixed in this version, its total in total of around $21k. The Push API feature is an optional feature, which means that you can enable or disable it as per your need. Push API allows websites to push notifications to you through your browser even when the browser window is closed.
Source: https://thehackernews.com/2015/04/download-google-chrome.html