Helldritch
Hero
And rightly so. There is a difference between setting which is homebrew to start with, even if official. A setting is homebrew. A corebook can be applied to any setting without changing the rules. XGtE, MToF are such books. We are talking about settings here. A setting can change just about anything that is assumed in the base games. Additionnal corebooks will not change the rules, but will clarify or add more rules.Okay. So that might not say what you think it says. He and I have been talking about settings, which is probably why even though he named only the core three books, he also only named settings.
If he did mean to include XGtE, then I will disagree with him. XGtE is outside of core, but it's not homebrew as it doesn't change the core rules so much as add new rules and ways to do things.