The Debian packaging of queue-el is maintained in git, using the
merging workflow described in dgit-maint-merge(7).  There isn't a
patch queue that can be represented as a quilt series.

A detailed breakdown of the changes is available from their canonical
representation - git commits in the packaging repository.  For
example, to see the changes made by the Debian maintainer in the first
upload of upstream version 1.2.3, you could use:

    % git clone https://git.dgit.debian.org/queue-el
    % cd queue-el
    % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'

(If you have dgit, use `dgit clone queue-el`, rather than plain `git
clone`.)

A single combined diff, containing all the changes, follows.
--- queue-el-0.2.orig/queue.el
+++ queue-el-0.2/queue.el
@@ -7,8 +7,7 @@
 ;; Maintainer: Toby Cubitt <toby-predictive@dr-qubit.org>
 ;; Version: 0.2
 ;; Keywords: extensions, data structures, queue
-;; URL: http://www.dr-qubit.org/emacs.php
-;; Repository: http://www.dr-qubit.org/git/predictive.git
+;; URL: http://elpa.gnu.org/packages/queue.html
 
 ;; This file is part of Emacs.
 ;;
