It comes more down to the design of the board and the quality of the other components on the board. The TPA3250 he mentions is quite a new chip, but if you look on Aliexpress for an older chip like the TPA3116 there is literally thousands of examples: https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...
I imagine this guy must have found the components of a site similar to DIY Audio. It would have been a nice addition to steer people in the direction of more information if they are interested in the topic (which a lot of the comments here seem to be asking about).