Case C-411/22, Thermalhotel Fontana: Judgment of the Court (Seventh Chamber) of 15 June 2023 (request for a preliminary ruling from the Verwaltungsgerichtshof — Austria) — Thermalhotel Fontana Hotelbetriebsgesellschaft mbH (Reference for a preliminary ruling — Social security — Regulation (EC) No 883/2004 — Article 3(1)(a) — Concept of ‘sickness benefits’ — Scope — Freedom of movement for workers — Article 45 TFEU — Regulation (EC) No 492/2011 — Article 7(2) — Social advantages — Difference in treatment — Justifications — COVID-19 — Isolation of employees ordered by the national health authority — Compensation of those employees by the employer — Reimbursement of the employer by the competent authority — Exclusion of frontier workers required to isolate under a measure taken by the authority of their State of residence)