An established project team with a good track record has been working on a project...

The Laissez-faire management style is characterized by a hands-off approach where leaders provide teams with resources and advice, if needed, but otherwise don’t interfere. This style is most effective with experienced, highly competent, and self-directed teams who are capable of performing their tasks without much supervision. In the context of the question, the project manager trusts the team and their work, indicating that they are likely using a Laissez-faire approach. References: 

https://www.g2.com/articles/project-management-approach