I had occasion to see government contract procured items (same as found on store shelves) religiously marked with expiration dates, when the ‘civilian’ product did not have exp dates.
As soon as it hit the expiration date, the government (military in my case) was mandated to destroy the items.
GINORMOUS amount of waste caused by this practice - but it keeps the boxes rolling out of the shipping departments.
Back in the 1960s I ate 10-20 year old military surplus rations. Don’t recall seeing expiration dates on them.