These are flows that will be prebuilt based on the available SKUs through the .Core platform. They can then be included as subflows into your flow, which will then allow your user to action those SKUs. These prebuilt flows will also include any validation or processes required for the specific interaction. For example, purchasing airtime for another user will include the required MNO lookup.
All prebuilt flows can be viewed in the Open Flow menu.
They are available for selection when configuring Menu Node.