ArcGIS Pro 2.6 API Reference Guide
DefaultExtent Property

ArcGIS.Core.CIM Namespace > CIMMap Class : DefaultExtent Property
Gets or sets the extent shown when you open new views of the map. The application automatically updates this property whenever you save a project with an active map view.
Syntax
public Envelope DefaultExtent {get; set;}
Public Property DefaultExtent As Envelope
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

CIMMap Class
CIMMap Members