A quiet announcement about a new Mozilla project sounded like a death knell for the Firefox browser.

It wasn't. But the project, called Tofino, reveals the technology challenges Mozilla faces more than a decade after Firefox's debut. Hundreds of millions of people still use the browser, but its star is fading compared with Google's Chrome.

Mozilla released details about the Tofino project Friday, saying a six-person team at Mozilla will consider how to radically revamp Web browsers.

"What we need a browser to do for us -- both on PCs and mobile devices -- has changed a lot since Firefox 1.0," Mark Mayo, senior vice president of the Firefox project, said in the first post on the Project Tofino blog.

"We're long overdue for some fresh approaches."

Fresh approaches, indeed. Instead of using the core tech of Firefox, called Gecko, Tofino uses an outside project called Electron built on Google Chrome's foundation called Chromium. That would be as surprising as Apple testing new iPhone interface ideas by using the Android software from archrival Google instead of its own iOS.

Mozilla is still staunchly backing Firefox and its core technology. But the fact that the Tofino team decided it could work faster with Electron shows how hard it is to keep up with Chrome, which is worrisome for Firefox's future.

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Although its glory days of running rings around Microsoft's Internet Explorer are long gone, Firefox still has an important role to play in driving progress on the Web. The Firefox team helps create and spread new tech standards that make the Web faster and give it new abilities with online chat, video games and virtual reality. And even if you primarily turn to apps on your phone, the Web remains fundamental to phones and PCs.

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Mayo knew the Tofino decision would be controversial, leading some to fret that Mozilla will ditch Gecko the way another browser maker, Opera Software, largely abandoned its own technology to move onto Chromium.

Internal resistance to Tofino has been fierce, he said.

"God knows the last month of stop energy should have killed it," Mayo said. "Years of fear of hurting Firefox, by rights, should have never even let the idea germinate."

As a measure of Chrome's power, consider the list of browser makers besides Opera that decided to build atop Chromium: South Korean electronics star Samsung, Russian search leader Yandex, Chinese Internet giant Baidu, Norwegian startup Vivaldi, and perhaps most tellingly, Brave Software, the San Francisco startup founded by Mozilla co-founder and former Chief Executive Brendan Eich.

Chrome accounts for 47 percent of browser usage, with Safari in second place at 13 percent and Firefox in third at 9 percent, according to measurements by StatCounter.

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Mayo's announcement displeased one Mozilla engineer, Kyle Huey, who blasted him in an email to all Mozilla employees for jumping the gun and bungling the news. In another project called Positron, Mozilla is adapting Gecko so Tofino can move off Chromium, but Mayo didn't make that clear in his announcement.

"Many people have spent a lot of time figuring out how to tell this story in a way that can't be mistaken as a vote of no-confidence in Firefox or Gecko," Huey said in the email seen by CNET. "It's hard not to see this as a mockery of both the legitimate concerns that were raised internally and the efforts of many people to address them before we announced this more widely."

Mayo updated his announcement to say that Tofino is aimed at experimenting with the browser user interface, not the core technology.

Huey didn't respond to a request for comment. However, his scathing email is actually an example of what's good about Mozilla, the organization argued.

"We work in the open, and we encourage our community to share their points of views. Sometimes that means respectfully disagreeing with each other," Mozilla said in a statement to CNET. "It's unabashedly Mozilla and not something we discourage."