From e15009f50e97e4291358db972cc0c2c630883dd3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Denis=20Bitouz=C3=A9?= <dbitouze@wanadoo.fr>
Date: Mon, 14 Jun 2021 18:06:25 +0200
Subject: [PATCH 1/2] Fix local assignment to a global variable
 '\g__sys_backend_tl'

---
 l3kernel/l3sys.dtx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/l3kernel/l3sys.dtx b/l3kernel/l3sys.dtx
index c7f0c1d2ed..c866b57490 100644
--- a/l3kernel/l3sys.dtx
+++ b/l3kernel/l3sys.dtx
@@ -487,7 +487,7 @@
       }
       {
         \tl_if_blank:nF {#1}
-          { \tl_set:Nn \g_@@_backend_tl {#1} }
+          { \tl_gset:Nn \g_@@_backend_tl {#1} }
         \@@_load_backend_check:N \g_@@_backend_tl
         \str_const:Nx \c_sys_backend_str { \g_@@_backend_tl }
         \__kernel_sys_configuration_load:n

From 2d3523a07fd0e2acd2a565fd31e9d6aba07f1495 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Denis=20Bitouz=C3=A9?= <dbitouze@wanadoo.fr>
Date: Mon, 14 Jun 2021 18:43:28 +0200
Subject: [PATCH 2/2] Update CHANGELOG (for PR/949) [ci skip]

---
 l3kernel/CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
index ce020127f4..d9761c08a8 100644
--- a/l3kernel/CHANGELOG.md
+++ b/l3kernel/CHANGELOG.md
@@ -7,6 +7,9 @@ this project uses date-based 'snapshot' version identifiers.
 
 ## [Unreleased]
 
+### Fixed
+- Local assignment to `\g__sys_backend_tl`
+
 ## [2021-01-09]
 
 ### Added