The Oracles Core Unit is responsible for developing and administrating the Oracle Protocol. See their mandate here.
Membership of the Oracles Core Unit can be seen in the @Oracles-Core-Unit group.
A Core Unit is a building block for organizing work for the DAO. Facilitators define long-term work areas and cover a broad set of focus and responsibilities for the protocol to be secure and successful. Core Unit Mandates set the direction of the work that Facilitators must help carry out. To read more about Core Units, head to MIP39: Core Unit Framework.