they're codenames from Google as to the 'flavor' of the most recent OS release. Alot of companies do this to refer internally to product that hadn't been released yet (Microsoft for example called one version of Windows prior to release 'Longhorn') and used to be you never saw the names unless you actually worked for the company, but more recently they release the names as a way to spice it up......my company has code names for product and when you look it up in within our internal tools, you see the name, but they mean nothing to people outside of the company.
