diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4596,7 +4596,8 @@
 
     With --graph the revisions are shown as an ASCII art DAG with the most
     recent changeset at the top.
-    'o' is a changeset, '@' is a working directory parent, '_' closes a branch,
+    'o' is a changeset, '@' is a working directory parent, '%' is a changeset
+    involved in an unresolved merge conflict, '_' closes a branch,
     'x' is obsolete, '*' is unstable, and '+' represents a fork where the
     changeset from the lines below is a parent of the 'o' merge on the same
     line.