I read comment, they said they used it as a treat for cat. So, this product is not for human?

These can be used for cats too. There are cat companies that sell half the amount of bonito flakes for 2x to 3x the price of the human version. I get these and the flakes are larger that my cats love. They go nuts when they see me open the bag.

What is the ingredient list, in English?

Not on this product but take a look at others - Katsuobushi Dried Bonito Flakes, Hime Dried Bonito Shavings Bulk, Marutomo Katsuo Bonito Flake - pretty much the same ingredients

Is this bonito salted?

Katsuobushi (what's shaved to make bonito flakes) is boiled, smoked excessively, then dried. There's no salt added, though because it's dried its sodium content is slightly higher (because all the water is gone; it's like concentrated fish) than the original bonito fish. But it's pretty negligible.