Implement DOM accessKeyLabel
Standard specification at https://html.spec.whatwg.org/multipage/interaction.html#dom-accesskeylabel
Already implemented in Mozilla Firefox.
Implementing this in Microsoft Edge would improve performance for websites using this (such as Wikipedia) by not having to load a polyfill that infers this information based on heuristics such as User-Agent strings and OS information.
This is a simple property accessed through the DOM that returns a string representing the keyboard combination used for access keys. This varies from browser to browser and between different operating systems and devices (mostly desktop however).