Hey Paul, can you give input on how important this is? 

Doesn't this already exist? Or is this different from the manifest property?

waiting on additional feedback.

GitHub issue:
https://github.com/w3c/manifest/issues/737

Discussion doc (Google only):
https://docs.google.com/document/d/1wchuU6uZAt10LYYL4U0GmI4lndwdkoMdvXKLiZkJ5Aw/edit

#4:
> Doesn't this already exist? Or is this different from the manifest property?

There's been some confusion because this feature keeps being labeled as "display: browser", which does already exist and has a separate meaning (specifically, that the app is opened in a regular browser tab).

This feature is about having a standalone app window with multiple tabs (containing separate documents inside the app scope) inside it.

Regardless of how we design this, the name of the feature proposal should not be named after a proposed solution, since that unnecessarily pigeonholes us into a particular solution.