Hello. My opinion is that this is indeed an item from Afghanistan. And this item can be called a "khyber knife". They are extremely variable, both in the shape of the handle and in the shape of the blade.
If you are interested in the arms of Afghanistan, you can learn a lot from this book: "Edged Weapons of Afghanistan 19th - early 20th Century".
If you are interested, I will write you the details in PM
It is a little more detailed than Egerton's data on arms of this country
