HDMI Forum is unwilling to disclose the 2.1 specification for open-source (Linux): according to AMD, they had submitted a functional, HDMI 2.1-compatible driver [for linux?], which the Forum rejected.

I do not really have a body for this. I was not aware that this is a thing and still feel like this is bs, but maybe there is an actual explanation for HDMI Forum’s decision that I am missing.