Pico-8 es_systems.cfg in Retropie

  <system>
    <name>pico8</name>
    <fullname>PICO-8</fullname>
    <path>/home/pi/RetroPie/roms/pico8</path>
    <extension>.p8 .png .sh</extension>
    <command>/home/pi/pico-8/customRunCommand.sh %ROM%</command>
    <platform>pico8</platform>
    <theme>pico8</theme>
  </system>