Bootstrap accessibility plugin set "tabindex" attribute to "0" for the first accordion panel heading and "-1" to the others so users can't navigate from one panel to the others. Tabindex shouldn't be setting for accordions.
And there is an "aria-selected" on the div.panel-collapse that is added. I don't think it is useful here.
P.S.: Why have you deactivated your bootstrap-accessibility.js on your demo site?
Hello,
Bootstrap accessibility plugin set "tabindex" attribute to "0" for the first accordion panel heading and "-1" to the others so users can't navigate from one panel to the others. Tabindex shouldn't be setting for accordions.
And there is an "aria-selected" on the div.panel-collapse that is added. I don't think it is useful here.
P.S.: Why have you deactivated your bootstrap-accessibility.js on your demo site?