Evaluating transfer rumors

In 2024, there were rumors about a buy-back for a player related to Real Madrid at 30M. However, Madrid reportedly has a 50% sell-on and a matching option rather than a fixed buy-back. The player might be available for 30M due to these rights. To clarify this, I'll provide a translation and brief context. Kubo is a key player for Real Sociedad and has garnered interest from clubs like Real Madrid and Barcelona. I'll also suggest potential follow-ups regarding his contract and performance this season.