How to find out which program is currently using my Microphone?

I have an orange dot floating in the top-right corner of my display. I believe that means that a program is using my microphone. Clicking on the dot doesn't do anything, hovering the dot doesn't do anything. But none of the programs in Preferences > Security & Privacy > Microphone are running, and I've even tried disabling them all but the orange dot didn't disapppear. I've even installed OverSight as [this question and answer suggest](https://apple.stackexchange.com/a/467548/150109) (because OverSight is the free option out of OverSight and Micro Snitch), but OverSight didn't identify anything. OverSight was working: I opened QuickTime to record a movie, and OverSight correctly identified that QuickTime was using the microphone. But when I closed QuickTime, OverSight reports that nothing is using the microphone, even though the orange dot persists. When quicktime is open, the orange dot was on the control center tray: When I quit QuickTime, the orange dot moves to the corner of the monitor and floats on top of everything all the time (even full-screen apps): Here's a gif of what happens to the orange dot when I open and quit quicktime, there's a smooth animation between the two orange dot states: I've checked Activity Monitor results for "audio", deleted a couple drivers (Zoom's and MSTeams' — apps which had long ago been deleted themselves) from /Library/Audio/Plug-Ins/HAL, but nothing is getting rid of the dot. How can I find out what is causing the orange omnidot? I'm hoping there will be a deep command line or private framework that might reveal the mystery.