This feature provides a JavaScript API to allow web developers to query and modify the "role" ARIA attribute directly. This implements attribute reflection for "role" attribute, similar to other attributes already supported like "ariaDescription" or "ariaRequired".
This is a kind of oversight from https://chromestatus.com/feature/6643371200217088, at that time all other ARIA attributes from the IDL (https://w3c.github.io/aria/#idl-interface) were shipped, but this one was missing. This is a small change that will also include the role attribute as one more of the reflection ARIA properties available. This should have shipped in M81 (https://groups.google.com/a/chromium.org/g/blink-dev/c/882iPcdnNQs/m/UP-PI8H2DwAJ) together with the rest of attributes, by for some reason this wasn't done (probably because it was originally developed under a different runtime flag).