Case C-802/19: Judgment of the Court (Seventh Chamber) of 11 March 2021 (request for a preliminary ruling from the Bundesfinanzhof — Germany) — Firma Z v Finanzamt Y (Reference for a preliminary ruling — Taxation — Value added tax (VAT) — Directive 2006/112/EC — Article 90(1) — Reduction of the taxable amount — Principles laid down in the judgment of 24 October 1996, Elida Gibbs (C-317/94, EU:C:1996:400) — Supplies of medicinal products — Granting of discounts — Hypothetical nature of the question referred — Inadmissibility of the request for a preliminary ruling)