public/Remove-PackageSource.ps1

function Remove-PackageSource {
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseShouldProcessForStateChangingFunctions', '', Justification='ShouldProcess support not required by PackageManagement API spec')]
    param (
        [Parameter(Mandatory=$true)]
        [ValidateNotNullOrEmpty()]
        [string]
        $Name
    )

    Write-Debug ($LocalizedData.ProviderDebugMessage -f ('Remove-PackageSource'))

    [array]$RegisteredPackageSources = Cobalt\Get-WinGetSource

    # WinGet.exe will not error if the specified source name isn't already registered, so we will do it here instead.
    if (-not ($RegisteredPackageSources.Name -eq $Name)) {
        ThrowError -ExceptionName "System.ArgumentException" `
            -ExceptionMessage ($LocalizedData.PackageSourceNotFound -f $Name) `
            -ErrorId 'PackageSourceNotFound' `
            -ErrorCategory InvalidArgument
    }

    # Cobalt will throw an exception if unregistration fails
    Cobalt\Unregister-WinGetSource -Name $Name
}