a minor glitch, at /u/USERNAME/preferences/account, Chrome OS devices are listed as ‘? unknown device’.
User agent string typically looks like:
Mozilla/5.0 (X11; CrOS x86_64 11895.118.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.159 Safari/537.36
(Chrome OS now >1% global PC OS market share, and >20% US laptop sales; big in education)