Ownership · The responsibility split · Element
Accountable and responsible
Who answers for it, and who actually does it.
The part
What it is
These are separated deliberately. The owner answers for the outcome; the responsible people produce it, and there may be several.
Where they are the same person, saying so explicitly avoids the assumption that someone else is covering it.
The smallest level
The attributes it carries
Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.