System.TimeZoneInfo.FindSystemTimeZoneById(String id) should be better documented.

Honestly, I wish this method did not exist at all as it would have encouraged me to look up 3rd party libraries like https://github.com/mattjohnsonpint/TimeZoneConverter right away. Instead, I spent hours debugging why it was functional on my computer (Windows 10) but not on the server (Windows Server). The function's dependency on the operating system should be explicitly mentioned in the XML comments.