from the explainer [0]: Portals enable seamless navigations between pages. In particular, we propose a new <portal> HTML element which enables a page to show an

from the explainer [0]: Portals enable seamless navigations between pages. In particular, we propose a new <portal> HTML element which enables a page to show another page as an inset, and then activate it to perform a seamless transition to a new state, where the formerly-inset page becomes the top-level document. Portals encompass some of the use cases that iframes currently do, but with better security, privacy, and ergonomics properties. And via the activation operation, they enable new use cases like preloading or navigation transitions. [0]: https://github.com/WICG/portals#readme https://github.com/WICG/portals#readme