I assume he's referring to this:
https://www.speedsolving.com/wiki/index.php/List_of_Unofficial_World_Records
This official mean is also the UWR (official or unofficial), as is his official average of 5 surrounding this mean of 3. Of course, this doesn't take into consideration the likelihood (probably pretty good) that Stanley may have a better one (or maybe many better ones) that he did at home that he simply hasn't told us about.