Notification sound when monitor is turned on

[Charles Dennett]

Running Fedora 40 on a desktop system with two monitors driven from 
built in graphics on motherboard (no separate video card). Yesterday I 
installed all updates including Plasma 6.2.  I've noticed that whenever 
I turn on a monitor I get a notification sound that I've never gotten in 
the past.  It's basically a two tone chime.  I've searched through all 
the notifications in the system settings app and cannot find one related 
to this.  I can't even find the sound file with the same sound.  I've 
had no luck with google nor KDE bugzilla.

What have I missed?  Where is this new notification specified?  I'm 
assuming it has something to do with the Plasma 6.2 update.

Thanks for any pointers.

Charlie Dennett