diff --git a/seahub/views/file.py b/seahub/views/file.py
index e92c8e79c4..5625547fd3 100644
--- a/seahub/views/file.py
+++ b/seahub/views/file.py
@@ -1256,6 +1256,7 @@ def file_edit(request, repo_id):
 @login_required
 def view_raw_file(request, repo_id, file_path):
     """Returns raw content of a file.
+    Used when use viewer.js to preview opendocument file.
 
     Arguments:
     - `request`: