Should this be an RFC?
Which package is this a feature request for?
SSR (@lit-labs/ssr)
Description
Context: #3677 (comment)
The ARIA attribute reflection logic in LitElementRenderer is dependent on our implementation of attachInternals() for HTMLElement in @lit-labs/ssr-dom-shim and may not work for users of other DOM shims. Currently jsdom nor happy-dom implement attachInternals() so there's nothing to support but we'll have to address this as ElementInternals gets wider adoption.
Alternatives and Workarounds
.