I've had some e-mails back and forth with the people at Stortinget (http://data.stortinget.no)
I personally thought of this category as all proposals to change the law. There are apparently some nuances here:
You’re absolutely right: “draft legislation” is basically the same as a bill, i.e. a proposal from the Government to change the law in some way. The Norwegian equivalent would be proposisjon til Stortinget (lovvedtak) (prop. L).
If the proposal were to come from one or more MPs rather than the government, and was intended to change the law, it would be representantforslag L. But this is less common and is not generally considered under the bracket of draft legislation.