Workspace Managers are likely to be working as a project lead or in a semi-administrative role within the project. There is no limit to the number of workspace managers in a single workspace.
Workspace Managers are similar to The Workspace Administrator but without the ability to approve an Airlock request. Managers are able to Administrate the workspace and its users. They can change the workspace description and icon and can add other users to the project.
Workspace Managers cannot add or remove Workspace Administrators or promote any other users to administrator. Managers can however cancel a pending invite for an Administrator.