Some of it is definitely UX polish, like if a button can be pressed to toggle a sidebar, then ESC should dismiss the sidebar and return focus to the button that toggled it. And when the sidebar opens, focus should be moved to the top of the sidebar.
Though you can also get trapped in a fractal of polish-chasing. When it comes to screen readers and live-content like a rich chat app or MUD client, I'm not sure how you would target anything more broad than, say, Safari + VoiceOver on macOS and then some other combo on Windows. You quickly realize the behavior you see is an idiosyncrasy in the screen reader itself.
I think this applies to anything :)
> You quickly realize the behavior you see is an idiosyncrasy in the screen reader itself.
Yeah this is definitely a pain point during development. There is standardization and efforts to reduce these differences though, so I hope this gets better over time.
> Consistent keyboard shortcuts across all features, and the ability to jump to any part of the interface by keyboard
This is something I notice and appreciate about VS Code as a fully sighted person. Just like I appreciate slopped sidewalk cutouts when I'm walking with luggage.
A11y is a big commitment and cost, and of course not all a11y features benefit everyone equally, but it has a larger impact than most people realize.