TElCRLNumberCRLExtension is a descendant of TElCRLExtension class.
This extension is used to contain a CRL Number.
The following paragraph is taken from RFC 2459 (Housley, et. al.), part 5.2.3:
«The CRL number is a non-critical CRL extension which conveys a monotonically increasing sequence number for each CRL issued by a CA. This extension allows users to easily determine when a particular CRL supersedes another CRL. »
CAs MUST include this extension in all CRLs.