Browser vendor makes a browser engine, and you believe they don&#x27;t plan to put it in the browser?<p>If you do a risky project that might fail or not pay off, and you don&#x27;t want to get bad PR, you can do only two things: Keep it entirely secret, or develop it in the open but make no promises whatsoever. For an open source company, the choice is pretty easy.<p>I always thought it was a public secret that <i>of course</i> they&#x27;re going to put it in the browser, but they don&#x27;t dare promising that before they know it&#x27;s going to work out. In fact, I wouldn&#x27;t be surprised if nextgen Firefox is just going to be Servo + browser.html.