The Free On-line Dictionary of Computing (30 December 2018):

Xilinx Netlist Format
XNF

    (XNF) A Hardware Description
   Language for electronic circuit design, developed by Xilinx,
   Inc..

   Xilinx-developed tools use XNF and handle the details of the
   FPGA architecture.  Converters are available for a number of
   widely-used HDLs - for example Verilog (xnf2ver) - so
   that designers can use familiar tools to develop Logic Cell
   Array designs.  In addition, XNF can be converted to the input
   language of different logic simulators.

   Specification
   (ftp://ftp.xilinx.com/pub/documentation/xactstep6/xnfspec.pdf).

   (1999-03-31)