Google has added popups that warn users of extensions that hijack proxy settings or the new tab page. The popups are part of Google’s plan to fight malicious Chrome extensions that have been starting to plague the Web Store. Extensions that programmatically change the startup page, homepage, search provider setting, or any other setting, must do it only via the Settings Overrides API starting with August 1. Google added the new popups to Chrome Canary builds (v62.x) in August.
Source: https://www.bleepingcomputer.com/news/security/chrome-adds-warning-for-when-extensions-take-over-your-internet-connection/