Note second Ubuntu hibernate blocker (pkla), PowerDevil cache gotcha, SleepMode=3

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

NEON-CUSTOMIZATIONS.md

@@ -162,8 +162,23 @@ Pieces:
   checks passed (seen with
   `systemctl service-log-level systemd-logind debug`). This rule sorts
   earlier and returns `YES` for local, active users.
+  Ubuntu actually has *two* blockers: that JS rule and
+  `/var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla`
+  ("Disable hibernate by default in logind/upower"), which is still read
+  because `polkitd-pkla` is installed. The `10-` rule overrides both:
+  `busctl call org.freedesktop.login1 /org/freedesktop/login1
+  org.freedesktop.login1.Manager CanSuspendThenHibernate` returns `yes`
+  as `matt`.
 - **Plasma**: PowerDevil owns the lid, so each Power Management profile's
-  sleep mode must be set to "Standby, then hibernate" in System Settings.
+  sleep mode is set to "Standby, then hibernate". That's `SleepMode=3`
+  under `[AC|Battery|LowBattery][SuspendAndShutdown]` in
+  `~/.config/powerdevilrc` (set 2026-09-28 for all three profiles).
+  **Gotcha:** PowerDevil caches hibernate support when it starts, so
+  after the polkit fix the option didn't appear in System Settings until
+  `systemctl --user restart plasma-powerdevil.service` and System
+  Settings was reopened. Check PowerDevil's view with
+  `qdbus6 org.freedesktop.PowerManagement /org/freedesktop/PowerManagement
+  org.freedesktop.PowerManagement.CanSuspendThenHibernate`.
 
 Tested 2026-09-28 with `systemctl hibernate`: a 3.8GB image, powered off,
 and the session resumed intact (uptime carried over, root `rw`). Right