This page is a draft of our policy regarding data package that depends on a binary package like *-data and *-music.
From the Debian Policy
Suggests: This is used to declare that one package may be more useful with one or more others. Using this field tells the packaging system and the user that the listed packages are related to this one and can perhaps enhance its usefulness, but that installing this one without them is perfectly reasonable.
Enhances: This field is similar to Suggests but works in the opposite direction. It is used to declare that a package can enhance the functionality of another package.
Enhances: is the best field to represent such dependency and should replace Suggests: but it's still not totaly supported (any pointed about that?)
Does it make sense to have the binary package in both the Enhances: and the Recommands field for a transition?