OID value: 0.9.2342.19200300.100.1.44
The Unique Identifier attribute type specifies a "unique identifier" for an object represented in the Directory. The domain within which the identifier is unique, and the exact semantics of the identifier, are for local definition. For a person, this might be an institution-wide payroll number. For an organisational unit, it might be a department code.
URL for further info: ftp://ftp.isi.edu/in-notes/rfc1274.txt
See also the OID Repository website reference for 0.9.2342.19200300.100.1.44