Request for Mozilla Position on an Emerging Web Specification

• Specification title: HTML
• Specification or proposal URL (if available): Add light dismiss functionality to <dialog> whatwg/html#9373
• Explainer URL (if available): Add light dismiss functionality to <dialog> whatwg/html#9373
• Proposal author(s) (@-mention GitHub accounts):
• Caniuse.com URL (optional):
• Bugzilla URL (optional):
• Mozillians who can provide input (optional): @smaug----
• WebKit Standards Position: Dialog closedby attribute and requestClose() function WebKit/standards-positions#329

Other information

This is a request for a Mozilla standards position on the idea of adding (optional) light dismiss functionality to Dialogs.
See whatwg/html#9373 for the discussion. The current proposal is a new attribute closedby (naming TBD) with three values, allowing no close bahaviour, close watcher behaviour, or close watcher and light dismiss behaviour.