diff --git a/lib/asciinema_web/live_stream_producer_socket.ex b/lib/asciinema_web/live_stream_producer_socket.ex
index da4ac3886..7ddc4aa8d 100644
--- a/lib/asciinema_web/live_stream_producer_socket.ex
+++ b/lib/asciinema_web/live_stream_producer_socket.ex
@@ -290,9 +290,12 @@ defmodule AsciinemaWeb.LiveStreamProducerSocket do
   @protos ~w(v1.alis v2.asciicast raw)
 
   defp select_protocol(protos) do
-    # choose common protos between the client and the server
-    # using client preferred order 
+    # Choose common protos between the client and the server using client preferred order.
     common = protos -- protos -- @protos
+    # Note the --/2 operator is right associative,
+    # and this would be more clearly expressed as 
+    #   common = protos -- (protos -- @protos)
+    # but mix.format removes the parenthesis ¯\_(ツ)_/¯
 
     List.first(common)
   end