Microsoft Defender SmartScreen flags LLVM Windows installer as unknown

I’ve downloaded LLVM-15.0.2-win64.exe from Release LLVM 15.0.2 · llvm/llvm-project · GitHub
When running it, Windows displays the message " Windows protected your PC. Microsoft Defender SmartScreen prevented an unrecognised app from starting. Running this app might put your PC at risk."

VirusTotal marks it as completely clean:

This might cause confusion and consternation for beginners. I don’t know what needs to be done so that Windows considers it “recognised”, although I suspect code signing would do it.