What does F4 button do in-game?

[BraveConquistador]

Sometimes I accidentally hit F4 when I try to reach for a quicksave, and when I do land on F4 my game freezes, FPS drops to 0, then slowly goes back to normal. What am I triggering?

[Трупоока Собака]

same

[MudMux]

If you are using UETools, it might me a hotkey for screenshot

[Christopher]

I used SysInternals Process Monitor and confirmed it is taking a screenshot. If I monitor the Stalker2-WinGDK-Shipping.exe process and press F4, it saves a high resolution screenshot here: C:\Users\[my user name]\AppData\Local\Stalker2\Saved\Screenshots\WinGDK.

The file sizes are quite large if you play at a high resolution.

[Mechanique]

It opens up your game settings where you can see what each button does