What each project role allows

You give a role when you give a colleague access to a project.

Role	What they can do
Lead	Everything on the project: its files, its state, publishing, reviews, sharing, deliveries and who holds a role on it.
Contributor	Add and remove files, draw on the map and write in the project's conversation.
Viewer	Open the project and its files, and write in its conversation.

People who are not listed

The owner, administrators, the organisation's billing and auditor roles, and people who hold a role on the project's branch reach the project through that wider role, so they are not rows in Members: they hold nothing on the project to take away.

People who reach the project through a team or a branch are not rows in the people list either. They appear as the team or the branch, in Teams and branches with a role, and leave when they leave the team.