Abandoned footwear means shoes that have been left behind by their owner and are now alone and lonely. Just like how you might feel sad if you were left behind by your friends at the park! It could happen for many reasons, like if someone lost their shoe while walking or if they just forgot it somewhere.
When shoes are left behind, they become "homeless" and don't have anyone to take care of them. They might end up getting wet if it rains or dirty from being on the ground. Sometimes people might find them and try to help them by putting them in a lost and found or giving them a new home.
But if no one comes to rescue them, the shoes will just stay there, waiting for someone to notice them and give them a new home. So always remember to take care of your shoes and make sure to never leave them behind!