Case T-380/17: Judgment of the General Court of 5 October 2020 — HeidelbergCement and Schwenk Zement v Commission (Competition — Concentrations — Market for grey cement in Croatia — Decision declaring the concentration incompatible with the internal market and the EEA Agreement — Undertakings concerned — Relevant market — Substantial part of the internal market — Assessment of the effects of the transaction on competition — Commitments — Rights of the defence — Partial referral to the national authorities)