Xbox one s power supply burnt?

My Xbox one s (approx. 6 years old) started to stink extremely overnight. We then disassembled it and found that the power supply unit, which is installed inside, is scorched. (see photos) I would be interested in how or why something like this happens and. Maybe one of you knows something.

Well that can happen after 6 years. Possibly there was always electricity on it for too long. It is therefore important to always disconnect electrical devices from the electricity. But that need not necessarily have been the reason here.