Plain text calendars like calendar.txt are great. [1] It would be super helpful, to see that list data in a month grid as well.

There's an Android app called Calendar Notes that does something like this, but it's not interoperable with Mac.

It could be a local file, an app, or a browser extension. Compatible with Mac desktop and Android phone.

Not looking for word processing calendars like Word or Google Docs. Also not Apple or Google Calendar. Really just plain text notes with a calendar-grid GUI. Thanks!

[1] https://terokarvinen.com/2021/calendar-txt/, discussed at https://news.ycombinator.com/item?id=31574125 (05/2022).

Edited for brevity.