When I run upower -i /org/freedesktop/UPower/devices/DisplayDevice (may be different on different machines, get a list with upower --enumerate), I get output similar to this:power supply:         yesupdated:              Thu 01 Jan 1970 01:00:00 AM CET (1444049000 seconds ago)has history:          nohas statistics:       nobattery  present:             yes  state:               discharging  warning-level:       none  energy:              47.716 Wh  energy-full:         47.716 Wh  energy-rate:         4.048 W  time to empty:       11.8 hours  percentage:          100%  icon-name:          'battery-full-symbolic'I'm wondering where the icon-names are defined. Is there a list with all possible battery-* icons?I found http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html, but it only lists battery-caution and battery-low. 
Where are upower's icon-names defined?
icons;freedesktop;battery
You can find full list of avaialable values for icon-name in upower source code.http://cgit.freedesktop.org/upower/tree/src/up-device.c#n99ac-adapter-symbolicbattery-missing-symbolicbattery-empty-symbolicbattery-full-charged-symbolicbattery-caution-charging-symbolicbattery-caution-symbolicbattery-low-charging-symbolicbattery-low-symbolicbattery-good-charging-symbolicbattery-good-symbolicbattery-full-charging-symbolicbattery-full-symbolicAnd XDG Icon Naming Specification is not related to them.