I think what’s implied here is the types of feeds which give a completely new content page when you “refresh”, so it’s not a regular “refresh-as-in-show-me-content-that-got-posted-since-last-access”, but an algorithm driven “refresh-as-in-replace” mechanism to increase engagement by continuing to provide stimulating content.

There was another one in Battlefield 1 - an experimental machine gun with two magazines, but only one could be engaged at a time. You would pull one out slightly and push the other one in. The idea was to be able to switch between two different types of ammo for increased versatility (e. g. regular ammo against infantry and incendiary for anti-air). As with most weapons featured in Battlefield 1, I think this was a prototype that never saw any real action.