eudc-inline-expansion-format

eudc-inline-expansion-format is a variable defined in `eudc-vars.el'.
Its value is

("%s" email)

Documentation:
A list specifying the format of the expansion of inline queries.
This variable controls what `eudc-expand-inline' actually inserts in
the buffer. First element is a string passed to `format'. Remaining
elements are symbols indicating attribute names; the corresponding values
are passed as additional arguments to `format'.

You can customize this variable.