Field parameters not in spec #134

From the source:

# The field class, as used by Link objects:

# NOTE: 'type', 'description' and 'example' are now deprecated,
#       in favor of 'schema'.
Field = namedtuple('Field', ['name', 'required', 'location', 'schema', 'description', 'type', 'example'])

But the spec for Link Parameters (which are the same thing as Field here right?) doesn't mention anything beyond 'name', 'required', and 'location'.

Q: What's the format of the schema parameter? Is this documented?

Thanks.

UPDATE: Looking further, other fields don't match either. e.g. Link has encoding, title, description which aren't in the spec either. What's canonical here?