diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
index 69c7dee1b9..3f87d7266b 100644
--- a/Documentation/git-ls-tree.txt
+++ b/Documentation/git-ls-tree.txt
@@ -78,6 +78,8 @@ Output Format
 
 Unless the `-z` option is used, TAB, LF, and backslash characters
 in pathnames are represented as `\t`, `\n`, and `\\`, respectively.
+This output format is compatible with what '--index-info --stdin' of
+'git update-index' expects.
 
 When the `-l` option is used, format changes to