These are application wide settings. They can often be set using the config file. Settings in the config file override these, even if these are changed. None of them are in the config file by default.
The archive path uses ruby-style interpoation for variables. Anything of form #{variable_name} is replaced. A media appends the file extension to this path; this path should point to the actual file to create (not just a directory).
The available variables are: