Request for position on an emerging web specification

Information about the spec

• Spec Title: Customized built-in elements
• Spec URL: https://html.spec.whatwg.org/multipage/custom-elements.html#customized-built-in-element

Bugs tracking this feature

• WebKit Bugzilla: https://bugs.webkit.org/show_bug.cgi?id=182671

Anything else we need to know

WebKit supports autonomous custom elements, but hasn't implemented this aspect of custom elements.

Colleagues and I wanted to share our thinking around that in this issue and also open it up for feedback from the community.