How does role=form help accessibility?
I have read that the role attribute was added to Bootstrap for accessibility, and I would like to know how <form role="form"> helps accessibility. See http://getbootstrap.com/css/#forms-example for an example of this specific usage.
I searched Bootstrap's repo for "role" to no avail.
My issue is that the information seems redundant. The notion that the element is a form is already expressed by the HTML tag itself (<form>), so what does it help if we also add that the element is playing the role of form? It would make sense to add role="..." if role was going to be different than form (I don't know what - but let's pretend); as it stands (especially without concrete reasoning / use case examples), it is puzzling at best.
Answer
If you add a role="form" to a form, a screen reader sees it as a region on a webpage. That means that a user can easily jump to the form with his/her region quick navigation keys (for example, in JAWS 15 you use R for this). And also, your user will be able to easily find where the form starts and ends because screen readers mark start and end of regions.