What this wiki has to say about one entry of my Google calendar. Online the calendar is drawn from a file of times, and an entry I have opened on purpose carries the words it carried in Google; this template lets the page carry them instead, in wikitext—with links, images, {{af}} tags and anything else a page may hold.

Write one anywhere on a page that shows the calendar, or on a page transcluded into it. Nothing appears where it is written: the widget takes the block and puts it in the card of the entry it names. At home, where the calendar is Google's own frame and the cards do not exist, the notes are listed under the frame instead; a reader with no JavaScript, and a printer, get that same list, which is why the block also carries a line saying which entry it belongs to.

{{Calendar entry|af=02HUG|title=Asurbanipal at the Caixa Forum|text=The Assyrian rooms first, then the café. Tickets are at the desk.}}

parameter	what it does
af	the Anno Fabri tag of the entry, as af2cal writes it into the description—AF: 02HUG on the first line. This is the key: it is how a note finds its entry, and why the tag is worth putting there.
on, at	a date, 2026-08-24, and—only if that day holds more than one entry—the hour it starts, 11:00. For an entry made in Google by hand, which carries no tag at all.
title	what the card should call it, when the title in Google is not the one to show a reader
where	likewise the place. A pair of coordinates is what Google stores when I drop a pin, and nobody wants to read that; where=- shows no place at all.
text, or the first unnamed parameter	the words themselves, in wikitext
instead=yes	show these words instead of the ones the calendar holds, rather than beneath them. Without it a note adds: what is in Google was read and cleared by hand through AUTO and is not dropped quietly.

The hours are the calendar's own and a note cannot argue with them—it may say what an entry is, never when it is.

A note whose entry is not in the calendar shows nowhere and costs nothing, so one may be written before the event exists and left there after the event has fallen out of the eighteen-month window. ?notes=1 on the page says which notes found an entry and which did not.

A bare pipe inside the text has to be written {{!}}; a pipe inside a link or a template is safe as it stands.