vpr/const/const.pb_type.xml

<pb_type xmlns:xi="http://www.w3.org/2001/XInclude" blif_model=".names" class="lut" name="CONST" num_pb="1">
  <input name="in" num_pins="0" port_class="lut_in"/>
  <output name="out" num_pins="1" port_class="lut_out"/>
  <delay_matrix in_port="CONST.in" out_port="CONST.out" type="max">0</delay_matrix>
  <metadata>
   <meta name="type">bel</meta>
   <meta name="subtype">constant</meta>
  </metadata>
</pb_type>