> Experts say the term “sell by” is generally for retailers to know when to rotate inventory, compared with labels like “best if used by” and “use by,” which indicate quality.

...

> Under the state’s bill, “sell by” dates can still be included on products as long as they are “coded” — information that is aimed at retailers rather than consumers.

This is about obfuscating "sell by" dates so customers don't get confused. They might not necessarily add another date you can read easily. Then if the grocery store forgets to replace old stock, you will never know.

But maybe someone can write an app to read the codes?