From an LWC perspective, what is in scope to be tested under WCAG 2.1 1.4.10 Reflow

Hi.

I’m interested in aspects of WCAG 1.4.10 Reflow as it relates to Lightning Web Components (LWC).  I’m not interested in how to test it; just simply what is in scope to be tested? My focus is on LWC which are designed to be placed in a page template component, but not page template components themselves.

I’m currently thinking that WCAG 1.4.10 Reflow is only applicable to LWC which:

1) are targeted at pages which themselves support a "Large" form factor;

2) either have no supportedFormFactors - so it is set by the page it is used in; or a supportedFormFactor set to "Large".

But, I wanted to reach out to the community for thoughts.   All comments welcome!  If it's already been answered somewhere, sorry.

I've considered the following resources to date:

supportedFormFactor as a child of targetConfig

From https://developer.salesforce.com/docs/platform/lwc/guide/use-config-form-factors.html

This governs the context in which the component is available - both by page and by viewing device. This means that via its config a component is restricted to specific pages it can be used in; and within that even specific devices it can be viewed by.

flexipageRegionWidth

From https://developer.salesforce.com/docs/platform/lwc/guide/use-width-aware.html

It deals with setting CSS - it is not just set at runtime.  Its value changes, and will update CSS throughout the period the page is loaded. This means that a user who chooses to resize their viewport might see different content relative to the size / selected breakpoints.

Valid CSS class values are SMALL, MEDIUM, and LARGE

screenResponsive="true"

From https://developer.salesforce.com/docs/atlas.en-us.exp_cloud_lwr.meta/exp_cloud_lwr/get_started_responsive_properties.htm

Deals with setting CSS - it is not just set at runtime.  Its value changes, and will update CSS throughout the period the page is loaded.  This means that a user who chooses to resize their viewport might see different content relative to the size / selected breakpoints.

WCAG 2.1 1.4.10 Reflow

From https://www.w3.org/WAI/WCAG21/Understanding/reflow 

Which seems to suggest that reflow should only be tested in a desktop environment, due to known support issues with browsers on mobile operating systems -> see sentence "The lack of magnified reflow support in browsers on mobile operating systems can therefore be regarded as a user agent support issue."