diff --git a/blake2b/blake2b_test.go b/blake2b/blake2b_test.go
index 723327a..08a9f93 100644
--- a/blake2b/blake2b_test.go
+++ b/blake2b/blake2b_test.go
@@ -14,6 +14,8 @@ import (
 	"testing"
 )
 
+var _ hash.XOF = (*xof)(nil)
+
 func fromHex(s string) []byte {
 	b, err := hex.DecodeString(s)
 	if err != nil {
diff --git a/blake2b/go125.go b/blake2b/go125.go
deleted file mode 100644
index 67e990b..0000000
--- a/blake2b/go125.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright 2025 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.25
-
-package blake2b
-
-import "hash"
-
-var _ hash.XOF = (*xof)(nil)