Created attachment 468335 [details] Repro HTML Relies on: https://bugs.webkit.org/show_bug.cgi?id=220719 Repro steps: 1. Go to https://codepen.io/nolanlawson-the-selector/pen/abXOKBO Expected results: The attributes `aria-braillelabel` and `aria-brailleroledescription` should reflect with the properties `ariaBrailleLabel` and `ariaBrailleRoleDescription` respectively. Actual results: The attributes do not reflect. Minimal repro: ```js const elm = document.createElement('div'); elm.ariaBrailleLabel = 'foo' elm.ariaBrailleRoleDescription = 'bar' console.log('aria-braillelabel', elm.getAttribute('aria-braillelabel')) // should be 'foo' console.log('aria-brailleroledescription', elm.getAttribute('aria-brailleroledescription')) // should be 'bar' ``` In Safari Technology Preview 179 (Safari 17.0, WebKit 18617.1.8.1), these log `null` rather than `"foo"`/`"bar"` respectively. ARIA PR: https://github.com/w3c/aria/pull/2057 WPT PR: https://github.com/web-platform-tests/wpt/pull/42751