Case T-515/18: Judgment of the General Court of 16 December 2020 — Fakro v Commission (Competition — Abuse of dominant position — Market for roof windows and flashings — Decision rejecting a complaint — Article 7 of Regulation (EC) No 773/2004 — Access to the file — Principle of sound administration — Reasonable period — Manifest error of assessment — Obligation to state reasons — No EU interest — Probability of being able to establish the existence of an infringement — Predatory pricing — ‘Fighting brands’ — Rebates — Exclusivity)