A model where a host project holds the network and service projects deploy resources into its subnets. It lets a central team manage networking while application teams manage their own projects.
The ACE asks about roles: Shared VPC Admin configures the Shared VPC, and Compute Network User, granted on a subnet, allows creating resources only in that subnet.
Shared VPC is a concept that can show up on the exam. Check the full guide to see it in context.