diff --git a/Sandbox/QuerypruneTest.txt b/Sandbox/QuerypruneTest.txt
index bdb165c7a..3c79f4931 100644
--- a/Sandbox/QuerypruneTest.txt
+++ b/Sandbox/QuerypruneTest.txt
@@ -1,5 +1,5 @@
 ! Title: ➗ Actually Legitimate URL Shortener Tool ($queryprune)
-! Version: 22November2020v5-Sandbox
+! Version: 22November2020v6-Sandbox
 ! Expires: 1 day
 ! From AdGuard CoreLibs (11/11/2020)
 $queryprune=|utm_source
@@ -76,3 +76,5 @@ $queryprune=|biw
 $queryprune=|bih
 ||google.$queryprune=|sa
 ||google.$queryprune=|ved
+! https://addons.thunderbird.net/en-GB/thunderbird/addon/mailbox-alert/?src=cb-dl-users
+||thunderbird.net^$queryprune=|src