And indeed, PalM 2 Bison is one of the LLMs covered in discussed link.
That doesn't change the fact that chat apps like Google Bard and Microsoft Bing, and even the ChatGPT app with plugins, are not foundational LLMs. The fact that they incorporate information from outside the LLM (usually in ways that are opaque to the user) gives them fundamentally different characteristics to LLMS.