tiny quantity of egg in a cookie (In the United States,) Keebler chocolate-chip cookies list egg as an ingredient. But they list it after salt, meaning that the amount of egg in the product is less than (well, not more than) the amount of salt. From the sodium content one can figure out that the amount of salt is not more than about five-sixth of a percent (or less than four grams per pound of cookies), so the amount of egg is also not more than that.

Why would they put in such a small quantity of egg? What does adding that small amount of egg do for the cookies, that they couldn't leave it out?
One thing to keep in mind is that they are in the "Contains 2% or less" section, which means they are exempt from the "descending order requirement". So all we know is that they are less that 2% of the total weight. I just looked at one typical chocolate chip cookie recipe that gave weights in grams, and it was 8% eggs by weight (114 grams out of 1419). So 2% isn't totally off the map - it probably is still enough to provide some binding and richness.