This field is used to link the product to another business object. it is very convenient to navigate to target business object via this kind of extension field.
In AET, Choose Application Reference as field type and opportunity as sub type.
Once you create new product, you can manually assign an opportunity to this extension field via F4 value help:
本文来自云栖社区合作伙伴“汪子熙”,了解相关信息可以关注微信公众号"汪子熙"。