Windows Terminal has support for unicode character display, etc. that the old cmd / powershell windows do not. This makes it difficult to create a shell profile (such as Microsoft.Powershell_profile.ps1) that works compatibly with both the old cmd / powershell windows and the new Windows Terminal.

If an environment variable was set by Terminal when hosting cmd / powershell / wsl, etc. it would allow users to detect they are hosted by the new Terminal and then enable use of unicode character display, etc. compatibly.

For example, my powershell profile prompt has been altered to include some emojis. In the old powershell window, this happens:

In the new Windows Terminal:

I could make my profile compatible with both if I had an environment variable to check.