Probably this is a naming issue.
Usually (milk) kefir is made with kefir grains. I also remember a bigger chunkier funghus from my childhood.
Then there is a fermented
dairy beverage called "kefir" by some. I once bought a little package of supposedly dried kefir starter but I am sure it is rather a mesophilic or termophilic culture for what we call Buttermilch as well - you can get buttermilk from the process of making butter and by culturing normal full-fat milk although the naming convention might not be correct.
For this cultured buttermilk you also add a bit of the last batch to the new one.
The description said it contains a mix of various lactic acid bacteria strains.
At the moment I am mostly making kefir with kefir grains, and if I make fresh cheese I use the buttermilk culture to make the milk acidic before adding the rennet.
I am only one, but still I am one. I cannot do everything, but still I can do something; and because I cannot do everything, I will not refuse to do something that I can do. (E.E.Hale)