I am confused about where SlowCheetah looks to determine which transforms to add.
When I go to build/Configuration Manager, I can add new profiles, then go to appsettings.json, right-click, Add Transform, and it will add a new transform (empty file) based on that profile.
However, if I delete the Release and Debug profiles from Build/Configuration Manager, then add transforms again, it still generates appsettings.Debug.json and appsettings.Release.json.
Is it looking somewhere else in addition to Configuration Manager profiles?
The confusion here was due to confusing behavior in Configuration Manager.
If you create a new configuration, in order to delete that configuration, you have to first delete it from the Active Solution Configuration dropdown, then delete it again from project's configuration dropdown (even if they don't have it selected). Definitely non-intuitive behavior from Visual Studio's build configuration manager.