Full page opened Pithos at a loopback address such as
127.0.0.1:58678/#/buckets/music-house, which means nothing to anyone
reading it and changes every launch. In Theseus the app now lives at
pithos.sia/<S3 user>/<drive>/<folder>, with pages at pithos.sia/settings,
/account and so on; the root page stays the pithos.sia website.
The add-on answers those paths through Theseus's new site routes. It
passes the session to the control server only for pithos.sia's own
requests and the address bar, never another site's fetch, and only
while the vault is unlocked, as the sidebar panel requires. The server
answers its own files, pages and existing S3 users and reports
anything else as not its own, so the website answers it. The sidebar
and the web console keep #/ addresses; an older Theseus still gets the
loopback address.