What is a new-tab-page-third-party in chrome?

Solution 1:

Looks legitimate

https://github.com/chromium/chromium/blob/52c4e0d606a975dc5c1315422fb31db9e4406782/chrome/common/webui_url_constants.cc#L130-L132

Here's the commit from 3months back that introduced this UI for the New Tab Page (NTP)

This CL creates a new default NTP for third-party search providers that do not have their own NTP define. It shows the most-visited tiles centered on the screen and can display a background is a chrome theme extension is installed. https://github.com/chromium/chromium/commit/dc334612cb78fa2233eb34c1355b6ee905f57cdc

Solution 2:

One advantage to the new-tab-page-third-party UI (intentional or un-) is, because it's search-engine driven it can act as a canary for search hijacking.

I recently worked on a system that previously had a bundled McAfee antivirus suite installed. Even after removal, it left a search hijacker behind that kept resetting Chrome's default search engine to their Yahoo!-based "Secure Search". The fact that the non-Google-branded new tab page kept coming up was the red flag that clued me in to the search modifications.