sS dm_ai_listAudioSources() {
  Cl l = cast dm_requireAndCall("#1020375/ListAudioSources", 'list);
  ret "There are " + n2(l, "audio source") + colonOrDot(l) + "\n"
    + mapToLines_rtrim(l, x -> "  " + get sourceName(x) + " (index " + get sourceIndex(x) + ")");
}