On an M4 Macbook Pro it's mild and faintly sweet but not really pleasant the way the LCD deck is. Requires a lot of heat for a long time to become noticeable. Vent is less convenient for sniffing.
Some conformal coatings, which protect PCBs from dust and moisture, can emit ethyl acetate or butyl acetate if they weren't fully cured. The smell is sweet but absolutely revolting.
