[arkits]

that's a pretty genius use of the "portals" primitive; I suppose its akin to Portals in React-ish.

Although I've never needed to open 2 tabs of the same site and wanted them share the state.

[kageroumado]

For me the main use case is screen sharing (share only the mirrored window). It can also be useful for multi-monitor setups when you want to show something to other people on a bigger screen without mirroring your main screen.