To download deployed WSP File from server use below code
$frm = Get-SPFarm $file = $frm.Solutions.Item("samplewsp.wsp").SolutionFile $file.SaveAs("c:\wsp\samplewsp.wsp")
To download deployed WSP File from server use below code
$frm = Get-SPFarm $file = $frm.Solutions.Item("samplewsp.wsp").SolutionFile $file.SaveAs("c:\wsp\samplewsp.wsp")