Here's a note from the Kumato website if you are also unfamiliar with the food. If you are lazy about linking, which I totally am, here's the summary (in UK English):
How are Kumato® tomatoes different from traditional tomatoes?
The colour of Kumato® tomatoes varies from dark brown to golden green. This is its natural appearance. Although they may look as if they are unripe and they will be bitter to the taste, this family of tomatoes has an authentic and intense flavour. They are sweeter than normal tomatoes, with a contrasting slightly sour note, which makes for a unique and clearly defined taste sensation. Furthermore, Kumato® tomatoes are very juicy and firm in texture, which means they are an excellent choice when preparing delicious salads and many tomato-based recipes.
Apparently they ripen from the inside out so there is none of that skin wrinkling. Particularly for a winter tomato, the Kumato was a very rich flavor that was not overpowered by the mozarella nor basil in this dish. I was pleasantly surprised and I would definitely recommend experimenting with these in your kitchen. Also I swear that the longer the slices sat, the more red they became. Maybe I am just going crazy, ha! The picture above doesn't doesn't really accurately represent the color difference between the two varietals so I included the dreaded winter vine for contrast below:
Blogger hates me tonight and no matter what I do to this image, it keeps posting as if I wanted it turned 90 degrees clockwise, which I didn't. Sorry. I'm tired of fighting with the machine tonight so hopefully I'll figure it out in the am, or if not, you can live with the twisted image. G'night xN