SubscriptionInfo

public Entry<ValueTuple<DataType, SecurityId>, long, ISubscriptionMessage, SubscriptionInfo> Entry { get; set; }

value = subscriptionInfo.Entry
subscriptionInfo.Entry = value

The registry record this info is the payload of. A linked view has none.

public CachedSynchronizedDictionary<long, ISubscriptionMessage> Subscribers { get; }

value = subscriptionInfo.Subscribers

The registry's own holder collection, handed over when the subscription was opened. There is one list of subscribers, not one here and one there.