Drainage pipe to nowhere
In most areas I'm familiar with, gutters don't drain into the sewage or storm drain systems. This looks like a flow diverter, but a very poor one. Are there any holes in the PVC pipe? The ones I've seen are much longer and have holes so they act like a French Drain but they usually head away from the house and not along side of it. You can just add a 90 degree bend to your downspout and direct the rain water away from your house.