FileType.Name
From Xojo Documentation
Property (As String )
aFileType.Name = newStringValue
or
StringValue = aFileType.Name
Supported for all project types and targets.
or
StringValue = aFileType.Name
Supported for all project types and targets.
The name used to refer to the File Type in your code.
Notes
This is what is shown in some open/save file dialogs. The Name property can be specified by a constant. When using dynamic constants, the names are automatically localized on macOS. On other platforms, the Name property will return the dynamic constant value, which allows you to register/update your file type with the system using the localized name.
Sample Code
The following defines the jpeg file type in code: