The Debian packaging of keysafe 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/keysafe
    % cd keysafe
    % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'

(If you have dgit, use `dgit clone keysafe`, rather than plain `git clone`.)

A single combined diff, containing all the changes, follows.
--- keysafe-0.20180326.orig/keysafe.init
+++ keysafe-0.20180326/keysafe.init
@@ -32,7 +32,7 @@ case "$1" in
 		start-stop-daemon --start --quiet --oknodo \
 			--background --no-close \
 			--pidfile "$PIDFILE" --make-pidfile \
-			--chuid keysafe:keysafe \
+			--chuid _keysafe:_keysafe \
 			--exec "$DAEMON" -- --server $DAEMON_PARAMS \
 			> /var/log/keysafe.log
 		log_end_msg $?
--- keysafe-0.20180326.orig/keysafe.service
+++ keysafe-0.20180326/keysafe.service
@@ -8,8 +8,8 @@ EnvironmentFile=-/etc/default/keysafe
 ExecStart=/usr/bin/keysafe --server $DAEMON_PARAMS
 InaccessiblePaths=/home /etc
 ReadWritePaths=/var/lib/keysafe
-User=keysafe
-Group=keysafe
+User=_keysafe
+Group=_keysafe
 StandardInput=null
 StandardOutput=journal
 StandardError=journal