Seems Windows 10 Mobile and Windows 10 Builds will go hand in hand as far as the build numbers are concerned. The latest Windows 10 Emulator has leaked on web and it runs the Windows 10 Mobile Build 10240. As you can see in the above screenshot the build is 10.0.10240.16384 and it is still marked as Insider Preview. So we can expect more builds till it RTMs in September.
Talking about changes the build seems to be scarce on visible changes but brings lots of polish and much better performance.
You can download and install the Emulator from here. Do let us know if you find anything interesting or a change from Build 10166.