Xbattbar shows the current (laptop) battery status in the X window
environment. Battery status is obtained through the APM kernel module.
The battery indicator of this program is very simple: a simple bar in
the top/bottom of your display. With its color, it indicates the
AC-line status (plugged in or off-line), and battery charging/remaining
level. Also, in the case the mouse cursor enters to the indicator window,
the popup diagnosis window comes up in the center of your display, and
then, it shows the current AC line status and battery level in the popup
window. This program is very small but fancy.

Homepage:
https://web.archive.org/web/20160729024814/http://iplab.naist.jp/member/suguru/xbattbar.html
