Naven
Glossary
Service worker
A script a site installs in the browser that keeps running when the page is closed.
It sits between the page and the network, which lets it cache files for offline use and, crucially, receive push messages when nothing is open. It is scoped to an origin and cannot see anything outside it.
It is also the piece most often responsible for a site serving a stale version, since a badly written cache never lets go.
Where Naven stands
Naven's service worker exists mainly to deliver notifications. It is scoped to the site root and holds no message content.