They mention that the F1 instance is using Xilinx's UltraScale+ FPGAs and that they have approx. 6800 DSP slices.

You can see that they must be targeting the VU9P from the product selection guide (pdf) here:

http://www.xilinx.com/support/documentation/selection-guides...

From the guide:

  VU9P:
    6840 DSP slices,
    2.3M flip-flops,
    1.1M LUTs
    36Mb distributed RAM
    76Mb block RAM
    270Mb ultra RAM

Additional documentation is linked on the last page of the selector guide.

Note that these specs are per FPGA. An F1 instance comes with up to 8 of these devices.