OID value: 188.8.131.52
Obsolete? From the Proposed Draft Amendment (PDAM) on ISO/IEC 9594-8 (ITU-T Rec. X.509): "This field enables distinct keys used by the same certification authority to be differentiated (e.g., as key updating occurs). The key may be identified by an explicit key identifier, by identification of a certificate for the key (giving certificate issuer and certificate serial number), or both..."
URL for further info: http://mlarchive.ima.com/pem-dev/1995/0241.html
See also the OID Repository website reference for 184.108.40.206