That skin is the default one with minimized margins, wiped out some images and some other "improvements" to fit in small screens, even in 800x600.
I hope it would be useful for netbook/pad users who feel lack of workspace.
I'm apologize for removing RC logo from skin - it's too expensive in area.
Installation:
# cp RC.04b.skin.small.tar.gz roundcubemail/skins
# cd roundcubemail/skins
# tar zxf RC.04b.skin.small.tar.gz
# rm RC.04b.skin.small.tar.gz
WARNING!
That skin is proven to work fine ONLY with RC-0.4-beta!But you can try in anyway, sure
That skin used as 0.4b was released, tested on 500+ humans, and shows no significant side effects.
Enjoy