Just checked. It is the league which receives the extra place. The extra place goes to the two leagues with the ‘highest coefficient’ (whatever that means?) in the PREVIOUS season. This is currently England and Spain.
The format of the 2024/25 CL competition will also change. Instead of qualifying groups there will be a league structure where each team plays 4 home and 4 away games to qualify for the knock out phase.
So, basically, 5th position in England should qualify forCL, whoever it is.