Google Chrome guards your new tab page and default search engine from being hijacked by malware, the browser asks, Is this the search page you were expecting when the default Search provider, which you use to search from omnibox has been changed by an extension, similar to that, Chrome also displays this notification from it’s menu ‘Is this the new tab page you were expecting?‘ when the new tab page has been altered.
Here is what the notification reads:
‘An extension has changed what page is shown when you open a new tab. If you didn’t want these changes, you can restore your previous settings.’
It offers ‘Restore settings’ and ‘keep changes’ button. Click on the former if you don’t know this happened without your knowledge, or keep the changes if you’ve intentionally installed an extension that changed the new tab page.
If you’ve missed that prompt, you’ll be warned when you visit the browser settings, you can notice an extension is controlling this setting with disable extension button message (this won’t goes away until the extension is deactivated or removed), for the open new tab page setting, under ‘On startup’.