A handy little cable that connects to the JST connector on the underside of HyperPixel 4.0, allowing you to use I2C devices with your Raspberry Pi at the same time as the display.
This 30cm-long cable plugs into the I2C connector on HyperPixel 4.0 (touch and non-touch) and breaks out the GND, SCL, SDA, and 3V3 pins from the Pi, letting you use any breakout that uses only I2C.
Note that the SDA and SCL pins broken out are the alternate I2C interface on the Pi that uses GPIO pins BCM 10 and 11, and that you'll need to enable the alternate interface by typing sudo ln -s /dev/i2c-3 /dev/i2c-1
in the terminal. You can find more details in Pimoroni's HyperPixel 4.0 tutorial.