For desktop use? Chroma subsampling is obvious. DSC compression, on the other hand, is not. DisplayPort and HDMI support both.

It’s obvious if you use a test pattern and/or know what to look for: https://testufo.com/chroma

I had no idea what it was for the longest time. As it turns out, macOS frequently enables it even when it’s unnecessary, and without any way to override.