There are a few cases where it is very useful to know the OS your .NET Core application is running on. One of those cases is when you need to set a time zone. Each OS does have its own naming of time zones. You can just try and catch the exception and then retry for another OS, however, if you know the OS, then it is far nicer to do this without exception handling.
Check the operating system .NET Core is running on. Sometimes there are small differences when running on Linux or Windows. Discover your OS without exceptions.