The nuances should be exposed in a stylable, implementable and a documented API, with examples and guidelines.
I don't understand why accessibility promoters endlessly bash developers, while the problem is that the edge between visual requirements and proper accessibility is extremely hard to dance, whereas it's mostly a non issue on proper platforms (eg. Cocoa/SwiftUI)
But… that’s when as a developer you push back. Visual requirements don’t take the place of accessible components in countries where there’s a legal requirement for accessibility, which includes most of north america.
In some cases the visual requirements are also accessibility-related.
For example, <select> will give you a drop-down that lets you type to pick, but only the first letter, and only letters that directly correspond with a keycode. So you can't type "Uni" to get "United States of America"; you can't type "とうきょう" plus enter to get "東京", and so on. If you need to support IMEs or picking through large option sets, dropdowns are a bad option.
Of course, native UI developers know that you can use a combobox instead of a dropdown picker; but there's no <combobox> tag. You have to implement your own by attaching a bunch of div/event soup to an <input type=text>[0]. In this particular case, doing so will actually make the input more accessible, because keyboard users can just type the answer instead of having to press the first letter and hit down 200 times to get to the thing they want. It's also more internationalized, because you can use your IME to compose the characters you need to search through the list with.
[0] The select2 library will do this for you and it's my go-to if I need a combobox.
Oh, 100%, if your designer is extending components with a mind for greater usability and accessibility then that’s perfect. There’s a reason ARIA exists after all.
In the US I'm fairly sure there's only a requirement for accessibility if you're building something for the government. I'm certainly allowed to build a website that isn't accessible and not have it taken down.
Edit: Guess there's precedent to require some businesses to do it as well. Looks like I'm mostly wrong here.
Judges have found that retail websites are subject to the ADA[1], and sites for things like utilities definitely are. Your personal website does not need to comply though, since it’s not considered a public space.
I don't understand why accessibility promoters endlessly bash developers, while the problem is that the edge between visual requirements and proper accessibility is extremely hard to dance, whereas it's mostly a non issue on proper platforms (eg. Cocoa/SwiftUI)