Remove entries in the logbook

Q: What do these remove entries in the logbook mean?

[2020/11/23 14:18:00] remove 20190720 Start
[2020/11/23 14:19:00] remove 20190720 End

A: These log entries come from the SD card's automatic purge. Here, the oldest day folder is deleted when it is filled to a certain extent, which is shown in the log in this way.