What is the purpose of App Service Stack Settings?

Question

What is the purpose of Stack settings in Azure App Service? I have .NET Core 3.1 app running without problems in App Service with Stack settings as on picture above. Should I modify my ARM Template to set Stack to .NET Core?

Answer 1

On windows OS that is only for initial creation.

After initial web app creation, there isn’t a need to identify that an app is a .NET Core app anymore because the .NET Core bits are already installed on the underlying worker. However for Linux App Service the stack settings will reflect .NET Core for an app, even after its created. MSDN Forum