File.rename-exclamation-mark

You're seeing just the function rename-exclamation-mark, go back to File module for more information.
Link to this function

rename!(source, destination)

View Source (since 1.9.0)

Specs

rename!(Path.t(), Path.t()) :: :ok

The same as rename/2 but raises a File.RenameError exception if it fails. Returns :ok otherwise.