Optional[customOptional[unknownOptionalendRestricted shows versions available only for internal Nebius use, mostly those about to get released to public. To use such versions - a feature restricted_k8s_versions should be enabled on a cluster.
Format of the version includes only MAJOR.MINOR, the same as can be passed to cluster creation API. For example "1.31".
EndOfLife determines when the version will be forced out of use.