The Rec. 2020 colorimetry is standardized in ITU-R BT.2020, but that is not all you all you will find there. That same document also specifies other aspects of a UHDTV video signal including the allowed resolutions (either "4K" 3840x2160 or "8K" 7680x4320) as well as the transfer function (gamma) which is the same as that of Rec. 709.
The Rec. 2020 standard does not include anything related to HDR since HDR did not exist at the time. It was only later that the Rec. 2020 color gamut was also adopted for HDR formats. So it is actually redundant to say SDR 2020. It should be calibrated the same way as Rec. 709 just with the wider color gamut instead.
Last edited by EvLee; 11-14-2017 at 06:42 PM.