What are activities and products and why are you not using the term “process” anymore?
In ecoinvent version 2 (except in the case of multi-output processes) both the activity which produces a certain product (such as steel production) and the product produced in that activity (such as steel) had the same name (such as "steel, converter, low-alloyed, at plant").
In ecoinvent version 3 the "activity" and the "product" are two separate entities. One product (such as steel) can be produced in different activities (such as "steel production, electric, low-alloyed" and "steel production, converter, low-alloyed"). The separation of the activity name from the process name allows a much simpler identification of different activities that produce the same product. It also allows the consistent creation of consumption mixes in the form of market activities, which group the suppliers of a product together.

What are the main features of ecoinvent version 3 which were not present in ecoinvent version 2?
What is the correspondence file? Where can I find it and for what it can be used?
Have the ecoinvent reports been updated for version 3 and where can I find them?
Where can I find the exchange which I know from version 2 in ecoEditor?