*     <li>"l" or "l(num)" - lowest version or bottom list of lowest ones filter</li>
     *     <li>"s" - contextual snapshot filter</li>
     *     <li>"e(G:A:V)" - predicate filter (leaves out G:A:V from range, if hit, V can be range)</li>
     * </ul>
     * Example filter expression: {@code "h(5);s;e(org.foo:bar:1)} will cause: ranges are filtered for "top 5" (instead

     * <code>groupId:artifactId:version</code> the returned identifier need not be complete. The identifier is derived
     * from the information that is available at the point the problem occurs and as such merely serves as a best effort
     * to provide information to the user to track the problem back to its origin.
     *
     * @return The identifier of the model from which the problem originated or an empty string if unknown, never