ubuntu-22.04.3-desktop-amd64/casper/filesystem/etc/alsa/conf.d/99-pulseaudio-default.conf.example

# Default to PulseAudio

pcm.!default {
    type pulse
    hint {
        show on
        description "Default ALSA Output (currently PulseAudio Sound Server)"
    }
}

ctl.!default {
    type pulse
}