Hi Dominic,
I wanted to make you aware of a discussion we will be having at TPAC regarding extensibility, web components, ARIA and a Java Script Accessibility API. We will be discussing your API work on Friday: https://www.w3.org/WAI/ARIA/wiki/Meetings/TPAC_2016. We would love to have you there at TPAC. I think you would need to join either the Web Platforms working group or the ARIA working group to attend.
Chris, you are most welcome to come and you have done such great work on webkit accessibility. I am working for the ARIA Working Group to meet with Web components earlier in the week.
Best,
Rich
Rich Schwerdtfeger