On page 32 of the game manual, there is a specification of two audio cues that warn and specify the existence of an endgame. But, due to my understanding of the rules, you can climb back on the hab zone at ANY point in the match (this is different from 2018). Why would there be a specification on the existence of an end game (TWICE!) if there isn’t anything that seems to be time sensitive.
TL;DR: Why does end game exist if I can climb at any time?
Probably mostly to remind the drivers that the end-of-game based scoring part of the game exists. When you are driving robots on the field and trying to do as much as possible, the 2.5 minutes fly by really quickly and it’s easy to lose track of time. The audio cues remind you that you have to actually go do endgame if you want to, else you probably wont have time to finish it all by the end of the match.
It’s not like two warnings is really going to hurt you, but it may very well help the driver who missed the first one, or who ignored it to finish scoring the piece on their robot and then realizes “oh crap yeah I should really do that now”
if you’re referencing G13, that only seems to be the case in the last 30 seconds of the match, similar to climbs given in 2018 if a robot had it’s bumpers fully inside the platform zone. it doesn’t necessarily give a ranking point, just one (1) level 3 climb at minimum (a robot with it’s bumpers fully inside their hab zone being contacted by an opponent may not necessarily be supporting other robots)