diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -3334,6 +3334,8 @@ def log(ui, repo, *pats, **opts):
     'o' is a changeset, '@' is a working directory parent, 'x' is obsolete,
     and '+' represents a fork where the changeset from the lines below is a
     parent of the 'o' merge on the same line.
+    Paths in the DAG are represented with '|', '/' and so forth. ':' in place
+    of a '|' indicates one or more revisions in a path are omitted.
 
     .. note::