diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index a8647fdb2803241ae7e4e4c04447b9734067098f..bdb2dc3db8cd88f395649e245d2ae6ec44205bb7 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -115,7 +115,13 @@ import qualified GHC.List as List ( foldr )
-- 'Data.Functor.Compose.Compose' are from "Data.Functor.Identity" and
-- "Data.Functor.Compose".
--
--- (The naturality law is implied by parametricity.)
+-- A result of the naturality law is the intuitive generalised identity law
+-- for 'traverse'
+--
+-- @'traverse' 'pure' = 'pure'@
+--
+-- (The naturality law is implied by parametricity and thus so is the
+-- generalised identity law [reference not available, word of mouth].)
--
-- Instances are similar to 'Functor', e.g. given a data type
--