It is a self-organizing team that is jointly responsible for the work. The Development Team itself determines how much work is included from the Product Backlog. The team also decides how they will do the work.
Just as the Product Owner determines the “what”, the Development Team determines the “how”.
They are responsible for the ‘SPRINT Backlog’
The important thing is that these people have the necessary competences. This is both about the knowledge they bring and the values they subscribe to.
The Scrum Guide describes the following values that everyone who participates in Scrum must subscribe to:
The Development Team consists of 3 to 9 people. In principle, the Scrum Master and the Product Owner may be members of the team.