The plan · The slots · Element
The milestones
The dates before publication.
The part
What it is
Draft due, review due, approval due. Worked backwards from publication using the measured step times.
A missed milestone is visible days before a missed publication, which is the point of having them.
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.