Does anyone know why they don't want to support right-to-left? I've seen tons of questions and posts about it over the years so I'm surprised that even with the next major release they aren't addressing it. Maybe I'm missing a perspective here though -- don't other people think that rtl should be a core capability of a framework like this? I'm also curious whether accessibility will be improved in 4.x.
However, it got abandoned, as far as I can tell from the outside, one of the people who manually creates an RTL version of Bootstrap basically called them imperialists for trying to automate something that was too precious to automate as it couldnt be 100% perfect and they caved to the pressure.
This is annoying for those that want to integrate CSS flipping into their own workflow.
Also, accessibility has been improving a lot recently, with PayPal and others contributing back and they announced Patrick Lauke would join their team to work on this.