No, it really isn't if you're not already into this type of app (and the recent trendy buzzwords around them). What it is: A note taking app using plain text files and giving great organization views. Nowhere on the main page does it say note taking app. Nowhere. You have to scroll to find "tend your notes like a gardener" as a clue that this is a note taking app. Anyone who hasn't looked at this space for more than 1-2 years will not know that "knowledge base" is investor-speak for "fancy note taking app".
Not that it makes much difference, but "knowledge base" is a much older term than 1-2 years. The Microsoft knowledge base is the first thing that came to mind, which started in 2003. Tools like Lotus Notes were using the term before that, but I can't find exactly when.
Out of curiosity I tried to find older references. There are references using this definition back to at least 1995. Beyond that it's trickier because apparently "knowledge base" was used to describe the knowledge available to an AI system during the expert systems era, which is a somewhat different definition. e.g. Lehnert 1977: https://files.eric.ed.gov/fulltext/ED150955.pdf
