The purpose of the slave saver is to align shaft movement precisely, so that the shaft has little or no side play, enabling the seals and washers to outlive their ungrateful installers.
The brackets have various shapes, depending on the transmission type. They usually bolt to the case and accept a heim joint for the true believers, who understand that a leaf falling from a tree in Baltimore affects the melting of the polar ice caps.
Now, I hope that answers your question, young Master Edward.