The wav files here are for the panel sounds; specifically the startup, shutdown and error sounds.

There are more here than I need, but feel free to remove them if The Macintosh Noise, boings, eeps and monkeys drive you mad.

If you want to remove the panel sounds, you will probably need to remove this line from panel.cfg:

gauge50=Boomerang_Sound!dsd_xml_sound2, 23,298,14,14,.\Aircraft\Rutan_Boomerang\panel_sounds.cfg