[Powershell] Anonymous Users cannot open XLSX files from a document library

sp-change-anonymous-perm-mask.ps1

[void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint")
$siteUrl = "<site collection URL>";
$site = New-Object Microsoft.SharePoint.SPSite($siteurl);
$web = $site.OpenWeb();
$enumPerms = [Microsoft.SharePoint.SPBasePermissions];
Write-Host $web.AnonymousPermMask64;
$web.AnonymousPermMask64 = $enumPerms::ViewListItems -bor $enumPerms::ViewVersions -bor $enumPerms::ViewFormPages -bor $enumPerms::Open -bor $enumPerms::ViewPages -bor $enumPerms::UseClientIntegration -bor $enumPerms::OpenItems
$web.Update();
Write-Host $web.AnonymousPermMask64;
$web.Dispose();
$site.Dispose();