The 6.7 default theme leans on patterns and style variations harder than any previous one, which makes it the clearest available reference for both.
what is worth reading in it:
eight full style variations, each a complete
theme.json rather than a colour swap
patterns as the primary unit — the templates are
mostly pattern references
section styles used throughout
a typography scale expressed in theme.json with
fluid ranges declared per size
what is not worth copying: the pattern count. 40-odd
patterns is a showcase, not a maintenance plan.
Reading a default theme once a year is the cheapest way to see what the current idioms are, and this one is more instructive than most because the variations are genuinely different rather than recoloured. Child-theming it remains the wrong move for client work for the same reasons as last year — the parent changes on WordPress’s schedule.