Thanks for sharing. Sounds interesting. I had been reading about various kinds [1] of fermented milk products recently, and had seen kefir among them.

[1] There seem to be many such kinds, across various countries.

Quark, skyr, doogh, kumis, buttermilk, dahi, chaas, filmjölk, blaand, ayran are some of the varieties.

Here's a list:

https://en.wikipedia.org/wiki/Fermented_milk_products