Comment by yihtserns

> Daily scrum, sprint planning, retrospective and review are ceremonies, and they are totally mentioned in the guide.

Those are "Events", activities to support development work. Unless you mean programming, testing, discussions, code reviews, etc are ceremonies as well?

> It’s true that scrum doesn’t directly mention story points but tell me whether story points or t-shirt sizing aren’t the two most common ways to size a story.

Borrowing your own words: "...story points aren’t in any way mandated by the..." Scrum Guide.