Sign-in button opens ping.omacom.io
Pull request 16186, merged into quattro, points the network check at ping.omacom.io and opens that address from the sign-in button. Major browsers had been forcing the old Arch address onto a secure page, so a sign-in page could not open.
The configuration points NetworkManager at http://ping.omacom.io/nm-check.txt, with an empty response, instead of ping.archlinux.org. The button reads "Sign into network".
archlinux.org sits on the browser list that forces its subdomains to a secure address, so the old button could not show a sign-in page. omarchy.org sends the same kind of instruction for its subdomains. omacom.io has not sent that instruction.
When a Tailscale exit node is active, the sign-in command pauses it, opens the portal in a floating window, and restores the node once connectivity is full. David Heinemeier Hansson wrote of a live check at a Mandarin Oriental hotel portal: NetworkManager reported portal, the page loaded, and 16 seconds later it reported full and the same exit node was restored.
There is no China-specific endpoint, so everyone uses ping.omacom.io for now. The Tailscale glyph ships with the font in omarchy-settings, so until that release the notifications show no icon on installed systems.
The version 4.0.6 notes say an existing machine can upgrade with Update > Omarchy.