Q:

How to find database name of \data\base postgres folders?

I have a large folder of 70 GB in my postgres installation under:
D:\Program Files\PostgreSQL\9.5\data\base\130205
Question: how could I find out which database is based on that folder?
I have like 10 databases running on the same server, and most of them having a tablespace on a different drive. 
But probably I'm missing a mapping somewhere, maybe a large index or kind of. How can I find out the "causing" database of these amounts of data?

A:

Thanks to the hint of @a_horse, the following statement shows the oid and table names:
SELECT oid,* from pg_database

