[TYPO3-calendar] What is startPointCorrection and endPointCorrection and what's a valid use-case for them?

[Simon Schick]

Hi, all

I had a quite long time debugging why none of my events were showing up.
Some of the events had no calendar that was related ... and events without
calendar aren't visible at all ..

Another reason was, that there was a value at the startPointCorrection and
endPointCorrection ...
What are these two values for and in what unit is the number I write?
Can you please show me a use-case for that?

Bye
Simon