It was explained by Pau Cubarsí on El Partidazo de la Cope. In Barça's locker room, there are five captains, but two players are in charge. They are the bosses of the locker room.
They have earned the group's respect, and their open and sincere demeanor has helped them become captains.
There are three more, but none lead like they do. Ter Stegen and Frenkie De Jong form a pressure group, with a voice and significant influence in the locker room, but they are below Raphinha and Araújo in the hierarchy.
Hansi Flick's Task for the Captains
Pedri, meanwhile, leads the group of young homegrown and Spanish players alongside Gavi. Íñigo Martínez is the one who uses his charisma to unite the synergies of all the groups. He belongs to everyone.

In contrast, Lamine Yamal, who is expected to have significant influence, barely has any authority among his teammates. They still see him as if he were the team's mascot.
Raphinha, Araújo, De Jong, Ter Stegen, and Pedri, as captains, received at the start of the season the task from Hansi Flick to maintain the harmony and unity of the squad.
The coach asked them to prevent any issues of coexistence from stalling and to come to him whenever they deemed it necessary.
The truth is that the health of the blaugrana locker room is excellent in terms of coexistence. Flick knew that the foundation of success was in good coexistence, and the captains have ensured it.
Neither Raphinha nor Ronald Araújo are the most veteran members of the squad, although they are not new to the club.

The Achievements of Raphinha and Araújo
Raphinha has earned authority within the group due to his demeanor, leadership ability, quality on the field, and international experience. He has played in Portugal (Vitoria Setúbal and Sporting de Lisboa), France (Stade Rennais), and England (Leeds United). His experiences are very important for a group dominated by young players.
Ronald Araújo, meanwhile, is a foreigner, but he has been at the club for many years. He came to sign for Barça Atlètic and from there made the leap to the first team as just another homegrown player.
That's why he is so appreciated among the homegrown players. He understands those who come from outside and those who arrive from within.
They are the bosses of the locker room. They are the ones who make decisions and negotiate with the coach, sporting director, or president any issue that may arise in the locker room.
They are also the responsible for a good internal atmosphere that has taken Barça to the top.