12 bit support? Encoder - what are the real specs?

I read in the AGX encoder specs that it has “12 bit support”

What does this actually mean?

We don’t give correct information about 12-but support. Please check

We support YUV420 10-bit H265 encoding, For more detail, please look at module data sheet:
Jetson Download Center | NVIDIA Developer

“we don’t give correct information” ?! seriously, this has been PUBLISHED all over the web for well over a year.