Window ▸ Share on Web Server serves a read-only copy of the document to your local network — colleagues on the same Wi-Fi open it in any browser, live. Edits re-publish as you save; encrypted pages are excluded; the server stops when you stop it or quit. The default port is 8080.
You'll always know when it's on: a checkmark appears next to Share on Web Server in the Window menu, and a “Sharing” badge lights up in the toolbar. Choose the menu item again — or click the badge — to stop.
This is for quick sharing in a room. For publishing to the world, use Static Publishing.