+ * @defgroup dbg_info Source References
+ * Firm requires a debugging module fulfilling this interface, else no
+ * debugging information is passed to the backend.
+ * The interface requires a datatype representing the debugging
+ * information. Firm supports administrating a reference to the debug
+ * information in every Firm node. Further Firm optimizations call
+ * routines to propagate debug information from old nodes to new nodes
+ * if the optimization replaces the old ones by the new ones.