This is an in-app reminder: the alert fires while this page (or the installed SCOB app) is open in the background — there's no server involved, so it works offline and needs no account. For a rock-solid nudge on session evenings, install SCOB as an app and leave it running, or also add the session to your phone's calendar. You can re-open this page any time to re-arm it.
The reminder is scheduled on this device using the browser's Notifications API and a local timer; nothing is sent anywhere. Session time is fixed to the SCOB public-night schedule (Friday 7:30 pm SGT). If notifications are blocked, the page still shows a live countdown and will pop an on-screen alert while open.