Sony FX 6 Quick Start Manual page 135

Cine EI: Gamma Display Assist
If you are using a LUT, then you don't use the Gamma Display Assist.
You can use the Gamma Display assist if you wish, instead of the a LUT.
Turning on Gamma Display Assist will make Slog 3 images look normal
in the camera viewfinder. But there is no advantage to doing this.
Gamma Display Assist will make the image appear normal in the
viewfinder but the waveform monitor will show the values of the
unaltered Slog 3 image.
So, if you use want to use the waveform monitor to judge exposure,
there is a mismatch between what you see in the VF and what values
are being represented in the waveform monitor. This can become
confusing.