presentation:start-scale - original size means?

19.422:

The presentation:start-scale attribute specifies the start size of a shape as a percentage of its original size.

The default value for this attribute is 100%.

Francis suggest it may mean the size of a shape at the beginning of an animation. Perhaps, but then why even mention it? Size of a shape is its size. Yes?

Anyway, I wanted to ask before the editors stumble over something know to implementers.