IsWindowsTerminal? who knows.

IsWindowsTerminal.ps1

function IsWindowsTerminal {
    <#
    .SYNOPSIS
    this is completely overkill and you should probably not use it.

    .NOTES
    the problem is:
    Start-Process -FilePath powershell -ArgumentList '-nop', '-c', '[bool]$env:WT_SESSION' -RedirectStandardOutput (Join-Path $pwd.Path 'foo.log') -UseNewEnvironment
    Start-Sleep 1;Get-Content .\foo.log;Remove-Item .\foo.log
    $env:WT_SESSION does not work if you start a shell directly, such as running powershell:
    from Start => Run => pwsh.

    only if you launch wt.exe does it get created.
    #>
    [cmdletbinding()]
    param(
        [Parameter(DontShow)]
        [Diagnostics.Process] $Process = (Get-Process -Id $PID),
        [Parameter(DontShow)]
        [Switch] $Breaker,
        [Parameter()]
        [Switch] $VersionInfo
    )
    function Out-TerminalInfo {
        param($found)
        if (!$VersionInfo.IsPresent) {
            return $found
        }
        if ($Process.ProcessName -eq 'WindowsTerminal') {
            $Edition = [regex]::match($Process.Path, 'Preview|Canary|Dev', 'IgnoreCase').Value
            if (!$Edition) {
                $Edition = 'Stable'
            }
        }
        [PSCustomObject]@{
            Success = $found
            Name    = $Process.ProcessName
            Edition = $Edition
            Version = $Process.FileVersion
        }
    }
    if ($IsLinux -or $IsMacOS) {
        return Out-TerminalInfo $false
    }
    if ($Process.ProcessName -eq 'WindowsTerminal') {
        return Out-TerminalInfo $true
    }
    if ($Process.ProcessName -in 'conhost', 'Code', 'Code - Insiders') {
        Write-Verbose ('Found non-windows terminal: {0}' -f $Process.ProcessName)
        return Out-TerminalInfo $false
    }
    if ($Process.ProcessName -match 'Alacritty|Hyper|Terminus|wezterm|rio') {
        Write-Verbose ('Found non-windows terminal: {0}, matching {1}' -f $Process.ProcessName, $Matches[0])
        # probably need to add more here..
        return Out-TerminalInfo $false
    }
    if ($Breaker.IsPresent) {
        # dont let it recursively check forever, after explorer we're done.
        return Out-TerminalInfo $false
    }
    if ($Process.Parent) {
        Write-Verbose ('Parent found: {0}' -f $Process.Parent.ProcessName)
        $PSBoundParameters['Process'] = $Process.Parent
        return IsWindowsTerminal @PSBoundParameters
    }
    if ($Process.ProcessName -eq 'explorer') {
        Write-Verbose 'Explorer but no breaker, happens if launch a shell from start => run directly, or doing weird stuff.'
        try {
            $oldTitle = $host.UI.RawUI.WindowTitle
            $str = 'IsWindowsTerminal: {0}' -f $Process.Id
            $host.UI.RawUI.WindowTitle = $str
            $Process = Get-Process | Where-Object { $_.mainWindowTitle -eq $str }
            $host.UI.RawUI.WindowTitle = $oldTitle
            # no more recursion pls.
            $PSBoundParameters['Breaker'] = $true
            $PSBoundParameters['Process'] = $Process
            return IsWindowsTerminal @PSBoundParameters
        }
        catch {
            return Out-TerminalInfo $false
        }
    }
    if (!$IsCoreCLR) {
        Write-Verbose 'Windows PowerShell, using CIM to get parent process.'
        $PSBoundParameters['Process'] = Get-Process -Id (Get-CimInstance Win32_Process -Filter ('ProcessId = {0}' -f $Process.ID)).ParentProcessId
        return IsWindowsTerminal @PSBoundParameters
    }
    return Out-TerminalInfo $false
}