diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 9bc292a39a..7cf91ac192 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -748,7 +748,8 @@ class YoutubeDLHandler(compat_urllib_request.HTTPHandler):
             gz = io.BytesIO(self.deflate(resp.read()))
             resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
             resp.msg = old_resp.msg
-        # Percent-encode redirect URL of Location HTTP header to satisfy RFC 3986
+        # Percent-encode redirect URL of Location HTTP header to satisfy RFC 3986 (see
+        # https://github.com/rg3/youtube-dl/issues/6457).
         if 300 <= resp.code < 400:
             location = resp.headers.get('Location')
             if location: