iCalendar appointment for "Patch Tuesday", or Microsoft's monthly patching day, the second Tuesday of every month @1700UTC.
Appointment time is in UTC, so it should work for importing into any timezone. There is no reminder set for this, so be sure to set one if you need it.
Subscribe to https://raw.githubusercontent.com/fexofenadine/mspatchingical/main/Patch%20Tuesday.ics