The video gives an example of performing simple component testing using a curve tracer or “Circuit Octopus” and an oscilloscope. It describes the Octopus, then delves into how to check resistors, ...

And as he intended to use it as an oscilloscope accessory, the analog output suited the application nicely. A pair of precision op-amps provide the voltage output scaled to 100 mV/A.

This particular video uses the Z-axis input on an analog oscilloscope. The input is composite video that's used to create X and Y sawtooth ramp signals from the vertical and horizontal sync pulses.