setContentProtection

Prevents the window contents from being captured by other apps.

On Windows, it calls SetWindowDisplayAffinity with WDA_EXCLUDEFROMCAPTURE. For Windows 10 version 2004 and up the window will be removed from capture entirely, older Windows versions behave as if WDA_MONITOR is applied capturing a black window.

On macOS, it sets the NSWindow's sharingType to NSWindowSharingNone. Unfortunately, due to an intentional change in macOS, newer Mac applications that use ScreenCaptureKit will capture your window despite win.setContentProtection(true). See here.