TElAuthorityKeyIdentifierCRLExtension is a descendant of TElCRLExtension class.
The following paragraph is taken from RFC 2459 (Housley, et. al.), part 5.2.1:
«The authority key identifier extension provides a means of identifying the public key corresponding to the private key used to sign a CRL. The identification can be based on either the key identifier (the subject key identifier in the CRL signer's certificate) or on the issuer name and serial number. This extension is especially useful where an issuer has more than one signing key, either due to multiple concurrent key pairs or due to changeover.»
Conforming CAs MUST use the key identifier method, and MUST include this extension in all CRLs issued.