The maxlen value is retrieved through the API - it's what Client Library (or in this case, FreeTDS) tells us that it is for this particular datatype/column.

You may want to ask on the freetds mailing list about this - I'm not a FreeTDS specialist by any means. However, the limitation is related to the TDS protocol version - if the client connects with TDS 4.2 then you won't be able to get wide varchar() columns, for example.

Michael