where are the message notification ringtones?

[shengchieh]

I would like to increase the volume (over 20 dB louder) when I receive a text message, but leave the phone notifcation
volume alone.  I do not see how I can do this in the setting (if possible, I must be blind - please tell me how).

So now, I want to increase the ringtones for message notification.  Where is it?

I already noticed

/usr/share/sounds/gnome/default/alerts/click.ogg
/usr/share/sounds/gnome/default/alerts/string.ogg
/usr/share/sounds/gnome/default/alerts/swing.ogg
/usr/share/sounds/gnome/default/alerts/hum.ogg

and increased the volume.  But these files do not get used for text notification (if they can, I must be blind - please
tell me how).  Instead I hear a  soft buzz whenever I receive a text.  Where is it?  I already searched for all the wav,
mp3, ogg, au, and raw files.

Fyi, I have the 32GB community edition Pinephone which was recently discontinued.  And postmarketOS v22.12 (haven't
update to newer version yet).

Thank in advanced for any help/tip.

Sheng-Chieh