I've been using Windows Terminal since the source code was released, and now that we have support for split panes, I wanted a way to easily create a tab with three panes (one for each version of PowerShell I want to test against).
Unfortunately, there's no support for opening tabs from the command-line yet, nor is there any support yet for specifying which profile to use in a new split terminal. There are open issues for those features, but although I've done a PR or two for it, I didn't think it would be an easy thing to pull together, but I knew that new tabs use the default profile.
Switching the default profile and then creating a new split with the hotkeys works great, but I wanted to set the default profile more easily than editing it in a text editor -- even though one of my profile hacks is to set the profile GUIDs to numbers I can easily remember.
Anyway.
I hacked this script together in the evening last night after my kids went to bed. It is exactly one "free time" worth of effort, so please don't expect it to be bug-free. One sad thing about it is that I have formatted it such that I can fold on braces and still see the profile and color scheme names -- but the script module below ruins the formatting if you change anything.
Unfortunately I don't have any json libraries handy that can modify json and leave it in it's current format. PowerShell turns everything into custom objects and hashtables, and pretty-formats the json (in a way that's wastefully huge) when you write it out.
I've also included my WindowsTerminal profile, as a reference (since it's working with this script module).