It's not from a leak. It's taking the system image from the SDK's emulator. This happens after every SDK release. These ROM's are intended to be more of a preview than anything else.the evo 4g has already got a 2.3 update, someone on xda ported it xF
so I guess they've already got some leaks.
Also, the PORT, has no source code attached, so, miui devs CAN'T put any features from that port on their ROMI don't think you all understand that there are no leaks for Gingerbread (except maybe for the N1) at this point in time. Anything "update" that is seen for anything outside of the N1 is a port from the SDK (Software Developers Kit) not AOSP (Android Open Source Project aka Source Code). The port is unstable and is meant as a preview of Gingerbread and should be used as such (Meaning not to be used for daily use as it may be unstable and things may not be working at the time).
I personally can't wait for Gingerbread and MIUI running on Gingerbread.