A low battery warning merged into quattro is sent as a normal toast that expires after 30 seconds on its own, and one restored after a restart leaves after the engine's short restore grace. On the new notification engine, critical toasts never expire and come back on every shell start, so once the warning was up it stayed after plugging in, after the level recovered, and across restarts and reboots on AC.

omarchy-battery-low already asked for 30 seconds, and only critical urgency overrode that. As an omarchy-action toast it still gets through Do Not Disturb, and the battery-low hook still runs. A warning sent while nobody is at the screen is gone after 30 seconds rather than waiting. The battery icon in the bar still shows the level.