See who can administer a project, and why

GET /projects/{project_id}/admins lists who can administer a project and how: through the team that owns it, an admin grant to them, or one to a team they belong to, as far as the caller may see. GET and PATCH /projects/{project_id} now return owning_team_id, and the person who claimed a project during local setup is listed through its owning team.

Project admins in the API reference