I think there was a thread here in the last few days that listed it's ingredients. I'd have to take a look at them. My guess right now would be that it would be fine as a small part of a very diet. I feed my Russian tortoise herbal hey during the winter. She only eats it if it's soaked and mixed with greens. You could try that with this food to see if your Russian would eat it. Buy a small container of it and seeing what happens.
Tortoise supply.com has what they call herbal hey. It is a bunch of different plants and herbs that are dried. It comes in 1 pound bags, but it lasts a really long time. It is chopped up into little pieces so it is not the typical hey like horses eat. My tortoise will only eat it if it is soaked and then next with greens. But I guess some tortoises just eat it plain.