Starting in 2.8.6, unofficial Windows Binaries have been labeled as YChat instead of XChat. This was changed in the source code prior to the release of 2.8.6 with the following code in src/fe-gtk/fe-gtk.h:
/* If you're compiling this for Windows, your release is un-official
* and not condoned. Please don't use the XChat name. Call it YChat
* or make up your own name! */
#define DISPLAY_NAME "YChat"
#define DISPLAY_NAME "XChat"
If you would like your copy of YChat to be named XChat instead, open up a hex editor and replace all instances of "YChat" with "XChat".
Most all of the unofficial builds of 2.8.6 will appear to be YChat unless the above change is made.