Hi Damon,
this cmdlet is part of the DynamicAxCommunity Powershell Module (here an
Introduction). Either the module is imported somewhere in the script using Import-Module, or it's used in Powershell 3+ where Modules are loaded automatically as required.
If the script is working that means it's installed somewhere on the executing computer, I'd recommend checking the Module folders ($env:PSModulePath will show you where).
If it's a script-module, you can simply read the function in your favorite script editor. If it's a compiled module, you'll need a library inspector, such as ILSpy, to read just what it's doing.
Cheers,
Fred
There's no place like 127.0.0.1