In 2019 Theo over at DomainGang.com posted about XMX.com selling for $3.9M. It was never added to Namebio.
From the article:
According to Chinese domain investor, Kassey Lee, the domain was bought by Hong Yu, founder of XMAX Foundation. The company issues XMX coins which are traded on a number of cryptocurrency exchanges.
On July 10th, Hong Yu posted on Weibo that he paid 350 BTC for the domain XMX.com
The domain name was left to expire and closed at $252,000 at GoDaddy auctions.
From Archive.org back in 2019:
XMAX is an entertainment-focused blockchain ecosystem with a “mainchain + multiple functional sidechains”, and provides a powerful SDK which simplifies the development process for entertainment DAPPs. Also, XMAX offers a variety of multimedia libraries and integrates an efficient game engine that makes it easier to represent digital items on the blockchain. The XMAX mainchain uses a VRF consensus mechanism and side-chains which operate on multiple consensus mechanisms to create a high concurrency, high TPS multi-chain system to allow for the creation of high-performance entertainment DAPPs.