This is something of an oddball issue, but I suspect there may be something of greater interest going on under the hood here.
I rebased my Silverblue install onto the 37 tree right before the original planned release date. Since then, GNOME’s alert sound - the little clip that plays when you try to backspace too far in the terminal, for example - has inexplicably been stuck on the old, removed defaultdrip.ogg - which, according to my repeated invocations of find, exists approximately nowhere on my disk.
Setting the alert sound in the GNOME control panel to one of the new options (such as “Hum”) has no effect; the new sound does play when you select it, but every other application is still somehow using “Drip,” including both Flatpaks and traditional packages.
Any ideas as to where this audio file could possibly be hiding/why my applications seem drawn to it like moths?
Disabling the terminal bell stops it in the terminal, but anywhere else that defers to the system alert sound (such as the Firefox Crtl-F dialog) will still exhibit the issue.
Edit: Also, I was able to fix it on one of my machines by doing… something in gconf/gsettings. I flipped the flag back and forth between a custom value and default a few times and it magically went away…
I first had to install pavucontrol, launch it, and in the Playback tab move the System Sounds slider around once. Then in MATE’s sound preferences I have to Mute the Alert volume. Just setting the sound theme to “No sounds” is oddly not enough.
See the difference in having the sound slider and Mute button enabled compared to above: