diff --git a/server/upstream/upstream.go b/server/upstream/upstream.go
index 8e50a1c..2afb5e6 100644
--- a/server/upstream/upstream.go
+++ b/server/upstream/upstream.go
@@ -21,7 +21,10 @@ type Options struct {
 	TargetBranch,
 	TargetPath,
 
-	DefaultMimeType string
+	// Used for debugging purposes.
+	Host string
+
+	DefaultMimeType    string
 	ForbiddenMimeTypes map[string]bool
 	TryIndexPages      bool
 	BranchTimestamp    time.Time