Miscelaneous ideas for mde.

Make a special "trace" logger which keeps the last 20, say, trace messages and only output them when asked to do so, which might happen when an exception is caught. It might output them via the normal mechanisms, but only when asked (and not all messages may be in the correct order: trace messages might be logged later than they were added to the list).

Use debug scope(failure) to output log messages in many places.