I'm sure they customized some of it, but this looks basically like Gemini integrated with iCloud instead of Google Workspace.
The text responses had Gemini's verbosity. Asking ChatGPT to show me iconic dishes from both Brazil and Morocco (Apple's example), is much cleaner, less verbose. Quick list of dishes and links to the recipe. Gemini just spews a wall of text and bullet points and goes on and on with fluff. Tons of "What this dish is" "Why it works" Same with its frequent use of tables, which I see less of with ChatGPT.
Each Siri demo they did in the keynote had that hallmark verbosity I typically get with Gemini without prompting it to not do that.
In my mind the Gemini LLM defines the bounds of capability and capacity, but any actual functionality or usefulness (or lack of) comes from Apple’s Siri harness.