Search notes:

*.format.ps1xml

Hash tables

It is not possible to use *.format.ps1xml files to customize how hash tables are displayed.

No format.ps1xml files in PowerShell 6 and later

Beginning in PowerShell 6, the default views are defined in the objects's source code.

Therefore, the *.format.ps1xml files from PowerShell 5.1 and earlier don't exist anymore.

However, it is still possible to create «own» *.format.ps1xml files to change the display of objects.

See also

Format for ps1xml files that specifies extended type data in PowerShell

The formatData command noun.