I'm playing a custom race that uses the Terran tech tree. The tooltip for the Research Treaty tech shows that it unlocks Slave Brokering instead of a research treaty. Having researched the tech, I can verify that in the trading window Slave Brokering is indeed what is made available for trading, which according to its tooltip does not give any research benefits. I see the Slave Brokering treaty in talking to both Iconians and Iridium.
