diff --git a/README.md b/README.md
index 61822e7..35bacbe 100644
--- a/README.md
+++ b/README.md
@@ -167,7 +167,7 @@ defined filter methods in the [dos2unix](./plugins/dos2unix) and
 [branch_name_in_commit](./plugins/branch_name_in_commit) plugins.
 
 ```
-commit_data = {'branch': branch, 'parents': parents, 'author': author, 'desc': desc, 'revision': revision, 'hg_hash': hg_hash, 'committer': 'committer'}
+commit_data = {'branch': branch, 'parents': parents, 'author': author, 'desc': desc, 'revision': revision, 'hg_hash': hg_hash, 'committer': 'committer', 'extra': extra}
 
 def commit_message_filter(self,commit_data):
 ```
diff --git a/hg-fast-export.py b/hg-fast-export.py
index 7c22d81..a4ced10 100755
--- a/hg-fast-export.py
+++ b/hg-fast-export.py
@@ -294,7 +294,7 @@ def export_commit(ui,repo,revision,old_marks,max,count,authors,
     brmap[name]=n
     return n
 
-  (revnode,_,user,(time,timezone),files,desc,branch,_)=get_changeset(ui,repo,revision,authors,encoding)
+  (revnode,_,user,(time,timezone),files,desc,branch,extra)=get_changeset(ui,repo,revision,authors,encoding)
   if repo[revnode].hidden():
     return count
 
@@ -308,7 +308,7 @@ def export_commit(ui,repo,revision,old_marks,max,count,authors,
     commit_data = {'branch': branch, 'parents': parents,
                    'author': author, 'desc': desc,
                    'revision': revision, 'hg_hash': hg_hash,
-                   'committer': user}
+                   'committer': user, 'extra': extra}
     for filter in plugins['commit_message_filters']:
       filter(commit_data)
     branch = commit_data['branch']