It seems like they might be running Redis Sentinels (for handling failover and replication), but exposing it outside as a single IP, instead of giving a list of

It seems like they might be running Redis Sentinels (for handling failover and replication), but exposing it outside as a single IP, instead of giving a list of sentinels to connect to. Applications might use that endpoint like a standalone Redis instance. Requests to that endpoint will be routed to the current master. Effectively abstracting the details about the Sentinels and their configuration from the clients. Not too sure, just a guess.