eli5 Eggs in the supermarket state on the box “Double Yolk”. Without cracking them, how do they know….?

Question

Apologies if this is ridiculous and should be in no stupid questions but it just struck me

In: 2748

Answer 1

When baking with eggs, unless going by weight not ‘eggs’ it’s really a bit of an art, not science.
How often does a recipe simply call for ‘an egg’ but is that a 50g egg, an 80g egg?

Either way, the weight of the egg is that specific/sold weight, even if it’s a higher portion of yolk to white.