diff --git a/kubernetes/apps/trmnl/renderer.yaml b/kubernetes/apps/trmnl/renderer.yaml
index 5c33db02..1625a1ca 100644
--- a/kubernetes/apps/trmnl/renderer.yaml
+++ b/kubernetes/apps/trmnl/renderer.yaml
@@ -29,6 +29,14 @@ data:
   # The app re-reads schedules.json every 60 s, so edits here take
   # effect without a restart once the init container has rewritten it.
   #
+  # lang is "de", not null. It calls Home Assistant's own
+  # _selectLanguage() for the screenshot session, so the rendered page
+  # is localised by HA rather than by hand. With it left null the
+  # dashboard grew a German weekday array, a German month array and a
+  # fifteen-entry weather-condition dict — reimplementing translations
+  # HA already ships. The instance itself stays language "en"; this
+  # only affects the render session.
+  #
   # model_id is 1 — TRMNL X (name "v2", 1872x1404, 16 colours) — and it
   # is an INTEGER, not a name. Confirmed against the running server:
   # GET /api/screens returns model_id as a number, and upstream's
@@ -61,7 +69,7 @@ data:
         "zoom": 1,
         "wait": null,
         "theme": "Graphite E-ink Light",
-        "lang": null,
+        "lang": "de",
         "dark": false,
         "invert": false,
         "timestamp": false,