It IS Lorem ipsum, and it's like that to indicate that there is something in that day, but it's written too small to be able to actually read it (without a magnifying glass or holding the phone incredibly close to your face). So the choice was made to use "filler text", instead of the actual event information.
The history of this goes back to the Windows Phone 7 days, when displays had a far lower resolution. Back then, it was acceptable to have some illegible text because no one could really read it.
If you refresh the calendar enough times, you'll spot some easter egg text in English.