Thanks. So it's building a hash tree with deterministic chunking and that means you can cheaply update the hash after updating parts of the tree as you only have to rehash certain bits?

Does that mean that your chunk sizes are kind of fixed? Do you think there's a way to retain that advantage and be able to coalesce smaller chunks into larger ones?

Say your smallest nodes are 4KB but for more efficient storage you might want to go up to 4MB chunks. Could that be done while retaining the same hash for the same underlying data?