There is a civic movement that wants to hold referenda to change the electoral systems. In effect, they want to make the list candidates more responsive to electoral districts. Typically, the closed list was replaced by an open list. The changes took place in Hamburg and Bremen. This meant that the members who were not elected by their constituency could be given preference by the electorate on the party list, so you could move them to the top of the party list.
This is the key point of these referenda or reform movements.