How a version differs between two states of the edition: whether it is in either, what it derives from in each, and which symbols it inserts and deletes in one and not the other.
Optional
The version it derives from in the state after, where it is in that state.
The version it derives from in the state before, where it is in that state.
How a version differs between two states of the edition: whether it is in either, what it derives from in each, and which symbols it inserts and deletes in one and not the other.