Currently they have three versions which show the same thing but use slightly different colors. By default they have "11.04" written in big letters and have a "days left" field with automatically updating "days" field.
Although I'm not sure if Canonical had used "symbols" other than the default Ubuntu logo, but interestingly, in all these banners we have a "Dolphin". Now according to experts the sign of the dolphin is not something that is just for beautiful looking... but it does have some deeper meanings too.
For instance, Dolphin represents kindness, fun, gentleness, intelligence, purity, etc. It has also been used as a "symbol protection" and most importantly is believed to be he symbol of the "generous spirit" as well. Anyway, Canonical had to face some "heat" from the community over few issue in the recent past and although not everyone was fond of the way they reacted either.
But if this is a way of Ubuntu to trying to be more gentle and drifts towards less aggressiveness and harmony... then I wish all the best to the Ubuntu team and good luck.