Egg-white protein does not always have to come from an egg laid by a chicken. The EVERY Company uses engineered yeast in a controlled fermentation process to produce a protein related to one naturally found in egg whites.
Its intended uses include baked goods, protein bars, dressings and other foods. In October 2023, the FDA completed its review of the company's GRAS notice and said it had no questions about the company's safety conclusion for the specified uses. That response is not the same as a traditional premarket approval.
The ingredient is not a whole egg grown in a laboratory, and being made without chickens does not make it suitable for someone with an egg allergy. The FDA letter specifically addresses allergen labeling. It also does not establish which particular supermarket products contain the ingredient; that requires checking the product itself.
Sources: FDA: GRAS Notice 1104 FDA: GRAS 1104 response and allergen labeling