Evolution · The fixed parts · Element

The permanent

Elements that will not change regardless.

The part

What it is

Usually the origin, the subject and one or two details that carry the recognition. Kept few, because a long list is not a commitment.

These are what a later version has to remain compatible with, which is what continuity means in practice.

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.