Definition of BUILTIN\Users?

For a server on a Windows Domain, what is the membership of "BUILTIN\Users" exactly?

(I figure this has an obvious answer, but googling hasn't given me any clear definitions)

From Microsoft KB 243330 Well-known security identifiers in Windows operating systems

SID: S-1-5-32-545

Name: Users

Description: A built-in group. After the initial installation of the operating system, the only member is the Authenticated Users group. When a computer joins a domain, the Domain Users group is added to the Users group on the computer.

When you install a Windows Server, the only member of the local Users group is local group Authenticated Users. Upon joining the server to your domain, the domain group EXAMPLE\Domain Users would be added to Users.