A reed switch (plus magnet and choice of location) would be an implementation of a 'fixed angle switch' per my comment above.

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vasco 6 days ago | parent [-]

If you approach something metalic to the top of the base in the left side of most macbooks you can feel where the magnet is. They either have both systems or maybe they switched this recently.

	▲	OJFord 5 days ago \| parent [-]
		Presence of a magnet doesn't imply presence of a reed switch - are you sure that's not just to give it some resistance to opening for example? Or angle sensing could be implemented with a magnet and Hall effect sensor.