gistfile1.txt

clear
$PAT=''
$Organization=''
$Project=""
$VariableGroup=""

$AzureDevOpsAuthenicationHeader = @{Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$($PAT)")) }
$UriOrganization = "https://dev.azure.com/$($Organization)/"

$uriVariableGroup = "$($UriOrganization)$($Project)/_apis/distributedtask/variablegroups?groupName=$($VariableGroup)&queryOrder=IdDescending&api-version=7.1-preview.2"
$VariableGroupResult = Invoke-RestMethod -Uri $uriVariableGroup -Method get -Headers $AzureDevOpsAuthenicationHeader

$AllVariables = ($VariableGroupResult.value[0].variables | Get-Member -MemberType NoteProperty).Name

Foreach ($vg in $AllVariables)
{
    "Varible group name: $($vg)"
    "Varible group value: $($VariableGroupResult.value[0].variables.$vg.value)"
}