+ * If is_new_ret is NULL, then a "file not found" message will be
+ * printed to stderr and NULL will be returned.
+
+ * If is_new_ret is non-NULL then a default configuration will be
+ * returned and *is_new_ret will be set to 1 on return so that
+ * the caller can recognize this case.
+ *
+ * These default configuration settings are determined as
+ * follows: