all longhand declarations must be inserted in canonical order with its physical longhands last (CSS Logical).

Unless otherwise specified, shorthand properties that encompass both logical and physical longhands (such as the all shorthand) set their physical longhands last.

In this sentence, I think last can be reasonably interpreted as:

• after all longhands
• or after all flow-relative (logical) longhands
• or after all flow-relative longhands of the same logical property group

Which one is it?

Apart from this requirement, what is the canonical order of all longhands? Is it the lexicographic order?