Import/Export Custom Product AttributesBrowser Info Environment
Exporting attributes would probably need to be done in name/value pairs, e.g. "animal=duck","size=large" otherwise the list of fields in the CSV file could get rather unwieldy if there are a lot of attributes defined but not necessarily associated with a product.
Importing might be slightly more interesting, since the values would need to be validated.
I have added this functionality to the roadmap