@zenbrowser Amazing! Does it replace the Firefox Multi-Account Containers addon?
https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/

Download Firefox Multi-Account Containers for Firefox. Firefox Multi-Account Containers lets you keep parts of your online life separated into color-coded tabs. Cookies are separated by container, allowing you to use the web with multiple accounts and integrate Mozilla VPN for an extra layer of privacy.
@timothee @zenbrowser Zen user here, not entirely (well, not without configuration). Spaces and containers are separate features, but spaces can be set to automatically load tabs in a particular container (or "profile" in Zen).
I presume with the routing feature the tabs that get moved will open in the container the space was configured to load tabs in.