finally It will be great to have an option to insert into epg the old vents available in the xml files. This is useful in case of crash, while epg is corrupt, no epg are shown.
What for? Have time machines been invented? What does the import of events that have already passed? And what does this have to do with any crash? This only leads to an increase in the import time and the size of the epg.dat(epg.db) file - no more
p.s.
In order to understand how EPG works on Enigma2, you need to delve into the source code of the epgcache.cpp file and the eEPGCache class in the enigma.py file of the image you are using. A lot of interesting things will open up for you ...