Here’s one good thing that’s popped up in Philly during the pandemic: community fridges full of free food to help people who have been struggling to make ends meet. It turns out the fridges are an example of something called “mutual aid,” which is a tradition in Philadelphia stretching back more than a century. WHYY’s Emily Scott digs into that history and explains how the tradition has shifted in response to different crises over the decades from helping free Black people after the Revolutionary War to COVID-19.