1 files changed, 2 insertions, 1 deletions
diff --git a/etc/NEWS b/etc/NEWS
index b1ad4dd1263..b10aa3b5a7d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -3858,7 +3858,8 @@ supporting Lisp files when 'require' is unsuitable.
 +++
 ** New function 'seq-union'.
 This function takes two sequences and returns a list of all elements
-that appear in either of them.
+that appear in either of them, with no two elements that compare equal
+appearing in the result.
 
 +++
 ** New function 'syntax-class-to-char'.