Why there is a different behavior between auto and small-auto ?

[fabien-michel]

I can't find, in the documentation, what is the difference between auto and small-auto classes (as well as shrink and `small-shrink).

But there is an obvious difference as shown in the demo below (with grid-y). auto fit the whole height, but small-auto doesn't.

Any idea why there is a different behavior ?

Demo: https://jsfiddle.net/z6fq813b/