Is there any directory server in public use?

Hi everyone

Can you give an example of directory server used by governments or certain authorities as to the source of truth? E.g. whether or not the person named so exists, or whether or not the land registered at certain street address belong to a Mr Smith?

I'm asking for this because I'm researching how the source of truth is made publically available in a public database with a set of open query method (like openldap filter) before the invention of blockchain. I personally also want to see such effort being made by willing authorities.

Thanks in advance!