diff --git a/share/man/man9/malloc.9 b/share/man/man9/malloc.9
index 71375e90951..c240344ea77 100644
--- a/share/man/man9/malloc.9
+++ b/share/man/man9/malloc.9
@@ -381,3 +381,7 @@ message.
 .Xr domainset 9 ,
 .Xr memguard 9 ,
 .Xr vnode 9
+.Sh HISTORY
+.Fn zfree
+first appeared in
+.Fx 13.0 .