diff --git a/ENV-NOTES b/ENV-NOTES
index 88ec4c8..f76af1c 100644
--- a/ENV-NOTES
+++ b/ENV-NOTES
@@ -82,3 +82,9 @@ UTXO_MB   - amount of UTXO and history cache, in MB, to retain before
             leveldb caching and Python GC effects.  However this may be
             very dependent on hardware and you may have different
             results.
+
+The following are for debugging purposes.
+
+FORCE_REORG - if set to a positive integer, it will simulate a reorg
+              of the blockchain for that number of blocks.  Do not set
+              to a value greater than REORG_LIMIT.
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