Hi,
Think it might be a Big Zebra, and it just might be solid red on inside. Nice looking tomato. If I am not sure about when it is rippened, usually by feel works.

Once a variety gets separated from its tag or label it becomes an orphan. Sigh.

What I'm saying is that we could guess and guess about it and still not know what it is for sure , unfortunately.

Is there any way that you could track it back to the trader and find out more information?

Stray seed of a known variety?

F1 hybrid from a natural cross?

All sorts of possibilities.

In the meantime, maybe best to enjoy it if it tastes good. ( smile)

Carolyn

Your tomato is probably whats called in the south a German tomato oralso known as an heirlom or ugly tomato and my they are ugly but the best tomato flavor ever ,they dont turn completly red they are deep almost black when ripe with dark green stripes. Make sure to keep seed for next year ,you will be pleased.