Add explanation to tensorfloat-32 disable decorator
diff --git a/tensorflow/python/kernel_tests/linalg/linear_operator_low_rank_update_test.py b/tensorflow/python/kernel_tests/linalg/linear_operator_low_rank_update_test.py
index aa4197c..be9f3ce 100644
--- a/tensorflow/python/kernel_tests/linalg/linear_operator_low_rank_update_test.py
+++ b/tensorflow/python/kernel_tests/linalg/linear_operator_low_rank_update_test.py
@@ -294,7 +294,8 @@
     config.enable_tensor_float_32_execution(False)
 
 
-@test_util.run_all_without_tensor_float_32("")
+@test_util.run_all_without_tensor_float_32(
+    'Linear op calls matmul which uses TensorFloat-32.')
 class LinearOperatorLowRankUpdateBroadcastsShape(test.TestCase):
   """Test that the operator's shape is the broadcast of arguments."""