I think the naming could be improved for OpenRealmBehaviorConfiguration. Currently it is:

{
  type: OpenBehaviorType;
  timeout?: number;
  timeoutBehavior?: OpenBehaviorType;
}

I think it should be:

{
  behavior: OpenBehavior;
  timeout?: number;
  timeoutBehavior?: OpenBehavior;
}

In my opinion, the "Type" word is too generic and its usage should be avoided unless it's really unavoidable.