diff --git a/packages/svelte/src/internal/server/dev.js b/packages/svelte/src/internal/server/dev.js
index efc761d7c5..2e40822705 100644
--- a/packages/svelte/src/internal/server/dev.js
+++ b/packages/svelte/src/internal/server/dev.js
@@ -24,7 +24,7 @@ import { HeadPayload, Payload } from './payload.js';
 let parent = null;
 
 /** @type {Set<string>} */
-let seen;
+export let seen;
 
 /**
  * @param {Payload} payload