These LEDs are designed for full color RGB digital displays according to Cree, although I can come up with more uses! They come in red, green, blue and amber. Cree claims, "Best matched and brightest 5-mm oval RGB LED series in the industry." Also available in a 4mm version.
The oval shape gives an elongated beam with an angle of 40 x 100 Deg. The epoxy encapsulant is the same color as the emitted light and is diffused a bit (you can still see the lead frame inside). As you can see, they are a lot smaller than an ordinary 5mm LED and has no flange, thus can be packed tighter on the PC board.
I have tested only the red so far. Good news as these are using Cree's newer high performance dies. The die cup is the anode on the red and probably the amber.