According to the What Is New in VMware vCenter Server 4 whitepaper, also connection information and certificates and thumbprints are stored in the ADAM database of a vCenter Server:
"Linked Mode uses Microsoft Active Directory Application Mode (ADAM), an implementation of Lightweight Directory Access Protocol
(LDAP), to store and synchronize data across multiple vCenter Server instances. ADAM is installed automatically as part of the vCenter
Server 4 installation. Using peer-to-peer networking, the ADAM instances in a group replicate shared global data to the LDAP directory.
The global data includes the following information for each vCenter instance:
• Connection information (IP and ports)
• Certificates and thumbprints
• Licensing information
• User roles"
Regards, Robert