Return the battery charge as a percentage (0-100).
level = MM.BATTERY%
On Linux the value is read from the first battery reported by sysfs at /sys/class/power_supply/BAT0/capacity. If that file is missing or unreadable, or on any other platform (Raspberry Pi / Circle, Windows, macOS), the function returns 100.
See MM.BRIGHTNESS% to read or set the display backlight on a laptop or Chromebook.
Example:
PRINT MM.BATTERY%Source: docs/help/mm-battery-percent.txt inmmcore. On the computer, typeHELP MM.BATTERY%.