diff --git a/lib/mint/http.ex b/lib/mint/http.ex
index 0178d58d..71c1c6ff 100644
--- a/lib/mint/http.ex
+++ b/lib/mint/http.ex
@@ -126,7 +126,7 @@ defmodule Mint.HTTP do
 
   @behaviour Mint.Core.Conn
 
-  @opaque t() :: Mint.HTTP1.t() | Mint.HTTP2.t()
+  @type t() :: Mint.HTTP1.t() | Mint.HTTP2.t() | Mint.UnsafeProxy.t()
 
   defguardp is_data_message(message)
             when elem(message, 0) in [:ssl, :tcp] and tuple_size(message) == 3