In Android to add ability to supply XXHDPI launcher icons for developer Android tablet releases.
So XXHDPI images can be supported on one of these folders:
- drawable-xxhdpi or
- drawable-480dpi folder.
According Google+ link extrahigh density (320 dpi) falls into XHDPI density bucket so this might be a duplicate request of https://jira.appcelerator.org/browse/TIMOB-7827.
The gorgeous screen on the Nexus 10 falls into the XHDPI density bucket. On tablets, Launcher uses icons from one density bucket up  to render them slightly larger. To ensure that your launcher icon (arguably your apps most important asset) is crisp you need to add a 144*144px icon in the drawable-xxhdpi or drawable-480dpi folder.