There's been a lot of talk about Project Spartan, the new browser that will replace Internet Explorer in Windows 10. That's also true for the version of Windows 10 that runs on smartphones, and for the first time, Microsoft is providing a glimpse of how Project Spartan's rendering engine (also called Project Spartan) runs on mobile handsets.
It's available in the Windows 10 Technical Preview for phones. As currently implemented, the Project Spartan rendering engine is baked into Internet Explorer -- Microsoft is saving a full-fledged browser replacement for a later preview. Essentially what that means is you can test drive the new rendering engine, just in a different skin (and presumably with a few less features) than the final, standalone version.
The Project Spartan engine will be used for all web pages loaded in IE on Windows 10 phones, so you don't have to guess whether you're experiencing Microsoft's newest code base or Trident, IE's previous rendering engine. And just like on PCs, IE will ignore "X-UA-Compatible" tags that try and force older compatibility document modes, Microsoft says.
Windows 10 Technical Preview became available for Windows Phones just a few days ago. Only a handful of devices are currently supported -- they include the Lumia 630, 635, 636, 638, 730, and 830. Noticeably absent from that list is the Lumia 520, a handset that comprises almost 30 percent of the Windows Phone ownership. However, that device only has 512MB of RAM. Microsoft's Joe Belfiore confirmed that it will be supported by Windows 10, though there will be some features left out.