Now that the charger knows that the cable can support 5 Amps, it sends a new Source_Capabilities message. In addition to 5V, 2.4A, it now includes 9V, 3A and 20V, 4.3A. Note that the 5V fixed supply is first, as required by the spec. Then all other options are listed in increasing order of voltage, in this case, 27W then 86W. Upon receiving the new capabilities, my board requests the highest possible power. Just like before, the charger sends an Accept message followed by a PS_Ready message.

Finally, the charger sends a Structured VDM to find out more about the device it's charging. Unfortunately, I haven't implemented that part of my firmware, so there's no reply.

That's the end of the transactions. After this point, the Easy Bake oven has the power it needs to run the heater. The Arduino inside is using its on-board regulator to convert the 20V down to 5V to power its microcontroller. In this system, there is no need for further communication. In a more complex version, the oven could send a request for less power when it knows it doesn't need to run the heater. This would allow the source to reallocate that power to other devices. This charger has only one USB-C receptacle and is only connected to my board and the wall, so there's no need for anything like that.