Defining the work · The definition of done · Element
The tail
What tends to remain after the main work is finished.
The part
What it is
Documentation, edge cases, training and the small things nobody scoped. The tail is where projects lose weeks.
Estimating it explicitly rather than assuming it disappears is what makes the end date real.
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.