I haven't looked into the logic behind which types' formatting data isn't being reported, but two examples are below.
A counter example is Get-FormatData System.Management.Automation.AliasInfo, which works as expected.
Steps to reproduce
Get-FormatData System.IO.DirectoryInfo, System.IO.FileInfo
Expected behavior
[System.Management.Automation.ExtendedTypeDefinition] instances describing the formatting, as usual.
Actual behavior
No output is produced; $? indicates $True.
Yet, formatting data is clearly in effect.
In Windows PowerShell, it can be discovered as follows:
Select-String -List System.IO.DirectoryInfo, System.IO.FileInfo $PSHOME/*.ps1xml
Environment data
PowerShell Core v6.0.0-beta.3 on macOS 10.12.5
PowerShell Core v6.0.0-beta.3 on Ubuntu 16.04.1 LTS
PowerShell Core v6.0.0-beta.3 on Microsoft Windows 10 Pro (64-bit; v10.0.14393)
Windows PowerShell v5.1.15063.413 on Microsoft Windows 10 Pro (64-bit; v10.0.15063)
I haven't looked into the logic behind which types' formatting data isn't being reported, but two examples are below.
A counter example is
Get-FormatData System.Management.Automation.AliasInfo, which works as expected.Steps to reproduce
Expected behavior
[System.Management.Automation.ExtendedTypeDefinition]instances describing the formatting, as usual.Actual behavior
No output is produced;
$?indicates$True.Yet, formatting data is clearly in effect.
In Windows PowerShell, it can be discovered as follows:
Environment data