diff --git a/api/auth/center.go b/api/auth/center.go
index 9de0105c..9bcdc70e 100644
--- a/api/auth/center.go
+++ b/api/auth/center.go
@@ -44,6 +44,7 @@ type (
 	prs int
 )
 
+// ErrNoAuthorizationHeader is returned for unauthenticated requests.
 var ErrNoAuthorizationHeader = errors.New("no authorization header")
 
 func (p prs) Read(_ []byte) (n int, err error) {
diff --git a/cmd/s3-gw/app-settings.go b/cmd/s3-gw/app-settings.go
index 4ae6af3a..6a4b6984 100644
--- a/cmd/s3-gw/app-settings.go
+++ b/cmd/s3-gw/app-settings.go
@@ -28,9 +28,6 @@ const (
 	defaultConnectTimeout  = 30 * time.Second
 	defaultShutdownTimeout = 15 * time.Second
 
-	defaultKeepaliveTime    = 10 * time.Second
-	defaultKeepaliveTimeout = 10 * time.Second
-
 	defaultMaxClientsCount    = 100
 	defaultMaxClientsDeadline = time.Second * 30
 )
diff --git a/creds/tokens/credentials.go b/creds/tokens/credentials.go
index a1aa2a86..903a74fe 100644
--- a/creds/tokens/credentials.go
+++ b/creds/tokens/credentials.go
@@ -114,7 +114,7 @@ func (c *cred) getAccessBox(ctx context.Context, address *object.Address) (*acce
 
 func (c *cred) Put(ctx context.Context, cid *cid.ID, issuer *owner.ID, box *accessbox.AccessBox, keys ...hcs.PublicKey) (*object.Address, error) {
 	var (
-		err error
+		err     error
 		created = strconv.FormatInt(time.Now().Unix(), 10)
 	)