A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
It turned out that the problem was pretty simple: the Microsoft Office Licensing setting (in MacOS Settings -> General -> Login Items & Extensions) had switched off somehow. I turned it off, logged out and in a couple of times and then it came back to life. (I'm running on a Mac Mini M4 with Sequoia 15.2)
I got this suggestion from Google with a little more than just a simple question. Context helped.