Leading male Italian footballers in the UEFA European national competitions 2020

The source explains that the FedEx Performance Zone is an algorithm used to identify "the form players in the UEFA Nations League and European Qualifiers".
Regarding the algorithm, the source specifies that "Every player is assigned a primary on-field position, where they are expected to play the majority of the time. The categories are goalkeepers, defenders, midfielders and forwards.
The data considered for each player is specific to their position. For example, clean sheets, tackles and recovered balls are considered key statistics for defensive players, while goals, assists, crosses and passes are important metrics for midfielders and forwards.
The algorithm uses player stats from matches in the UEFA Nations League, European Qualifiers and international friendlies, delivering updates after these games are played. On all matchdays where matches in either competition are played, the rankings update live as the games unfold".