diff --git a/scrapy/utils/response.py b/scrapy/utils/response.py
index f1efa2b73..4e0d31736 100644
--- a/scrapy/utils/response.py
+++ b/scrapy/utils/response.py
@@ -48,7 +48,6 @@ from scrapy.http import (
 from scrapy.utils.decorators import deprecated
 from scrapy.utils.python import to_bytes, to_unicode
 
-_baseurl_cache: "WeakKeyDictionary[Response, str]" = WeakKeyDictionary()
 _ENCODING_MIME_TYPE_MAP = {
     b'br': b'application/brotli',
     b'compress': b'application/x-compress',