Transparency - To effectively inspect and adapt it is important that the right people can see what is going on. But this is actually much harder than it looks. The scrum master is tasked with ensuring that the scrum team works in a transparent way. Examples include creating story maps and updating confluence pages with retrospective ideas.
Empiricism - A fundamental for scrum and agile approaches the idea that the best way of planning is to do work and learn from it. Empirical process is not easy and requires the scrum master to coach the scrum team on breaking down work, describing clear outcomes and reviewing those outcomes.
Self Organization - Telling a development team they can self organize does mean that the team will self organize. In fact self organization comes over time and requires help and support. The scrum master will encourage team members to step outside their comfort zone and try different things and use practices such as ‘delegation poker’ to expose and challenge predefined ideas about role boundaries and responsibilities.
Values - Scrum defines 5 values of courage, focus, commitment, respect, and openness not because they are nice to have, but because they create an environment of physiological safety and trust. This environment is necessary for agility to thrive. Following the values is the responsibility of everyone in the scrum team, but the scrum master takes an active role in encouraging and reminding everyone of the importance of those values.
Development Team
Delivering the work through the sprint.
To ensure transparency during the sprint they meet daily at the daily scrum ( sometimes called a standup). The daily scrum provides transparency to the work and provides a dedicated place for team members to seek help, talk about success and highlight issues and blockers. The scrum master might facilitate the daily scrum, but ultimately it is the responsibility of the development team to run this meeting. It is their meeting to help them, as a group, to inspect and adapt the work they are doing and work in a more effective way.
Product Owner
Managing the task backlog - This does not mean that they are the only one putting in new product backlog items into the backlog. But ultimately they are responsible for the backlog that the development team pulls to deliver from. That means the product owner should know about everything that is in the backlog and other people that add items to the product backlog should ensure that they communicate with the product owner.
Release management - The sprint is not a release cycle, but instead a planning cycle. That means that scrum teams can deliver at any time. Ideally, they would deliver frequently throughout the sprint allowing the sprint review to review real customer usage and feedback. However continuous delivery is not always possible and other release models are required. It is important for the product owner to know when things can and should be released.
Stakeholder management - Any product will have many stakeholders involved ranging from users, customers, governance and organizational leadership. The product owner will have to work with all these people to effectively ensure that the development team is delivering value. That can mean a large amount of stakeholder management and communication.