more NEWS;

--- a/NEWS	Wed Dec 23 23:21:51 2020 +0100
+++ b/NEWS	Thu Dec 24 00:07:51 2020 +0100
@@ -13,6 +13,9 @@
 included distinct_subgoals_tac no longer affects unrelated subgoals.
 Rare INCOMPATIBILITY.
 
+* HTML presentation includes auxiliary files (e.g. ML) for each theory,
+with rich markup.
+
 
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