Describes a problem that was encountered during settings building. A problem can either be an exception that was
thrown or a simple string message. In addition, a problem carries a hint about its source, e.g. the settings file
that exhibits the problem.
Gets the hint about the source of the problem. While the syntax of this hint is unspecified and depends on the
creator of the problem, the general expectation is that the hint provides sufficient information to the user to
track the problem back to its origin. A concrete example for such a source hint can be the file path or URL from
which the settings were read.
The hint about the source of the problem or an empty string if unknown, never null.