MBR3 is a register configurable device via I2C interface.
The CY8CMBR3xxx configuration registers are configured via I2C interface using one of the following methods:
1. EZ-Click 2.0
2. Third-party Programmer
3. Host APIs
4. Bridge Control Panel
You were probably refering to the the Host API's.
Ez-Click is a graphical user interface (GUI) used to configure the CY8CMBR3xxx CapSense
controller. It takes all the required parameters, and configures the device via I2C interface from the host computer with appropriate connections.It is Windows GUI-based tool has been improved to make development of capacitive user-interfaces extremely simple and quick without any firmware development.
Refer to section 5.2 of MBR3 design guide
The below video gives you an introduction to the tool,
Also see Ez-click user guide for more details