How can I identify what is happening when I press PrintScreen?

On my Windows 11 Home machine, when I press PrintScreen, it's doing something, but I can't figure out what.

Things I've checked:

• I have Greenshot installed, which is what I'd like it to be using, but it isn't
• I've checked Settings → Accessibility → Keyboard, and "Use the Print screen key to open screen capture" is turned off
• I've checked the keyboard shortcut for screen capture in the GeForce In-Game Overlay, and it's something else. I've also disabled the In-Game Overlay

When I press PrintScreen, my screen briefly goes dim, and there is a brief flash of the notification icon in the bottom right, which disappears immediately afterwards.

If I have the notification panel open when I press it, there's a brief flash of a notification that appears before disappearing. It is too fast to read, but when I record a slow-motion video of my screen, I can see that it is telling me that "Do not disturb" is on.

If I open up Settings → System → Notifications and press PrintScreen, I can see “Do Not Disturb” flashing on and off again.

Things I've tried to identify if it's something nefarious:

• Run a Bitdefender scan on my system which didn't turn up anything.
• Used Wireshark to look at outgoing traffic.
  • I left it running for a while (without pressing PrintScreen), and then filtered out all destinations that had come up.
  • When I pressed PrintScreen, there wasn't any additional traffic.
• I wrote a Python script that continually checks the process list and flags when a process starts or stops. It may not have been fast enough (it may not catch a process that takes less than about 12 ms), but it doesn't seem that whatever this is is starting up a new process.

What can I do to figure out what's holding onto this? If it's something nefarious, then I'll want to get rid of it, but if not, I just want to unbind the key so that I can use it in the application that I want for screenshots.

I rebooted into safe mode, and had to use a wired keyboard, as my usual keyboard (Logitech MX Keys) wouldn't work without Bluetooth enabled. When I tried PrintScreen on the other keyboard, it didn't do anything in Safe Mode.

However, when I restarted back into normal mode, I wanted to ensure that the PrintScreen button on the wired keyboard did the same thing as on the wireless keyboard, and it turns out it doesn't. PrintScreen on the wired keyboard does exactly what I'd expect it to.

So it seems that my issue is that the PrintScreen button on my wireless keyboard is doing something other than what I'm expecting. Further investigations are required.

I never thought to check the clipboard. I was only checking the standard screenshots folders. Yes, there's a full screen screenshot in the clipboard. (I would prefer it to go via Greenshot and give me a region to select.)