Accessibility: enhance UX for keyboard and novice users with shortcut keys-help

[MarcusMorba]

I am currently wondering, why the 3D viewer has no build-in help option to display available keyboard shortcuts as a help.

Besides that I wonder if it would make sense to offer additional visible buttons to control the viewport.
Have there been made some user tests and UX-research on this?

Would love to align UX and a11y-efforts between different 3D content viewers, e.g. from Sketchfab & Europeana:

• https://weave-3dviewer.com/asset/177b605a-9a31-4813-bb33-77075a5351e1 (Europeana Weave 3D Viewer)
• https://www.europeana.eu/en/item/1061/LIMIS_110000013755838 (uses Sketchfab)

[MarcusMorba]

Would love to have some examples with the above mentioned features in the a11y-section or even better an a11y-section on its own: https://modelviewer.dev/examples/loading/#useA11y