Unzip the file and it will become a .syx file. This can then be imported into FM8 via its file menu.
I created these on a classic Yamaha TX802, the rack version of the DX7. The file inside this zipped file is a system exclusive (sysex) dump, and can be imported by NI's FM8, as well as other virtuals that can convert DX7 sysex files.
Have a ball! firstname.lastname@example.org