The typical underengineered battery cable end that is too small and then overheats over long term use to melt the plastic insulation. To create massive sales of OEM battery cable sets since they are assemblies that cannot use the normal battery cables you find in the parts stores.
New battery cable time. I made up my own battery cables many years ago out of bigger cables to stop that issue forever.
Leave the pretty battery cover off and the original type cables will last longer, the cover stops fan air from cooling the cable ends off to get even hotter.
There was a recall years ago on the early cars over this, they sometimes caught on fire when the plastic began to burn.
The main bulk of the terminal shown there is crap too, the bolt will tighten like tight but the terminal can still be moved by hand (loose) even with bolt very tight if the terminal gets cleaned inside the post bore to get to fresh clean lead for a better connection. Ford idea of that clamp type was a massive fail that causes lots of trouble when people think the cables are tight but they easily spin loose. Next the alternators then blow out from overwork when the bad connection stops alt charging from getting to the battery, the alts are weak and known for that.