diff --git a/4.2.4-Header-Editor.md b/4.2.4-Header-Editor.md
index e11373e..0b7a297 100644
--- a/4.2.4-Header-Editor.md
+++ b/4.2.4-Header-Editor.md
@@ -7,6 +7,7 @@ Header Editor is an extension that allows you to modify the request header and r
 :small_orange_diamond: remove all ETag's
  * Note: if you disable disk *and* memory cache, this is not required
  * Test: https://httpbin.org/
+ * Test: https://privacycheck.sec.lrz.de/passive/fp_etag/fp_etag.php
  * Test: http://lucb1e.com/rp/cookielesscookies/
    * number of visits should never be more than 2
    * note: the site uses IP and UA to create your unique ID, so to test, do not change these