lattice/ice40/primitives/sb_lut/sb_lut.model.xml

<!-- set: ai sw=1 ts=1 sta et -->
 <models>
  <model name="SB_LUT4">
   <input_ports>
    <port name="I0" combinational_sink_ports="O" />
    <port name="I1" combinational_sink_ports="O" />
    <port name="I2" combinational_sink_ports="O" />
    <port name="I3" combinational_sink_ports="O" />
   </input_ports>
   <output_ports>
    <port name="O" />
   </output_ports>
  </model>
 </models>