The XR thread at Namepros is one of the more active.
Back in 2019 Wired published a primer article on the topic.
“XR does not refer to any specific technology. It’s a bucket for all of the realities.” Jim Malcolm, HumanEyes.
Basically it’s an umbrella term for mixed realities. MyXR.com sold for $17,000 in 2017.
Namepros member @MattG hit a homerun with GolfXR.com today.
Congrats to Matt.