"Guideline 3.4 Make content usable in device orientations." possibly more suited under "Principle 4: Robust"?

[patrickhlauke]

In current proposed https://w3c.github.io/Mobile-A11y-Extension/ we have

Guideline 3.4 Make content usable in device orientations.[MOBILE]

3.4.1 Orientation: Orientation of the content is not locked to landscape or portrait, except where orientation is essential.

I'm wondering if this wouldn't fall more under Principle 4: Robust? While at the moment this principle seems concerned with "mechanical" robustness (that UAs, including AT, can interpret content correctly)

Principle 4: Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

it "feels" to me that having content/applications that work well in different viewports/screen sizes/screen orientations is also a measure of robustness (though admittedly, to make it fit, this may require an expansion to the "Principle 4" wording to allow for new SCs other than purely mechanical ones to be included.

[patrickhlauke]

An alternative would be to move the proposed guideline 3.4 under "Principle 1: Perceivable - Information and user interface components must be presentable to users in ways they can perceive.", and more explicitly under "Guideline 1.3 Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure." - however, I feel this would cover only the visual/presentational aspect, rather than also any functional concerns (that content should also "work" in different orientations)...or perhaps I'm overthinking this part?