Starting in December, Firefox will use Yahoo as its default search engine in the United States on mobile and desktop. As a part of this five-year deal, Yahoo will also launch a new search experience for Firefox users in the U.S., which should go live at the same time Firefox makes the switch away from Google.

The new search experience will feature “a clean, modern and immersive design that reflects input from the Mozilla team.” Here is what that will look like:

In Russia, Mozilla will use Yandex Search and in China, it will use Baidu as the default. Google, DuckDuckGo and a number of other local search engines will remain as built-in alternatives.

The Mozilla Foundation has long made most of its money through its search partnership with Google, which has always been the default in Firefox. Indeed, in 2012 — the last year we have data from — 88% of Mozilla’s income came from Google. That contract with Google was set to expire this year, though, and it look like either Yahoo made an offer Mozilla couldn’t refuse or Google decided to walk away from the deal.

“Google has been the Firefox global search default since 2004. Our agreement came up for renewal this year, and we took this as an opportunity to review our competitive strategy and explore our options,” said Chris Beard, Mozilla’s CEO in a statement today. “We are excited to partner with Yahoo to bring a new, re-imagined Yahoo search experience to Firefox users in the U.S. featuring the best of the Web, and to explore new innovative search and content experiences together.”

Likewise, Yahoo’s CEO Marissa Mayer today noted that she believes that “search is an area of investment, opportunity and growth for us. This partnership helps to expand our reach in search and also gives us an opportunity to work closely with Mozilla to find ways to innovate more broadly in search, communications, and digital content.”

Yahoo Search, in its current form, is powered by Microsoft Bing, of course, though the company heavily modifies the results it gets from Microsoft, both in terms of layout and ranking. There have long been rumors that Yahoo could end this deal and bring back its own search engine, but that seems unlikely given the investment the company would have to make after it dismantled its old search engine infrastructure.

This partnership with Firefox will surely give Yahoo — and Microsoft — a stronger presence in the search market, however. While Firefox usage has declined over the last few years, it still accounts for at least 15% of the U.S. browser market. Yahoo currently owns about 10% of the U.S. search engine market. Switching the default back to Google only takes a few seconds, but most users will likely stick with the default.