Binary package “cbatticon” in ubuntu mantic
lightweight and fast battery icon status and more
Utility that displays battery information as battery status, remaining
percentage, remaining time, using an icon in the system tray.
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Based on code from xbattbar-acpi, cbatticon sits in your system tray,
reporting on battery events, like plug-in, critical, remaining, etc.
.
A regular user can (re)define custom system's behaviour, like performing
graceful shutdown on critical status, by user-defined thresholds and commands
on low power/critical.