Nintendo has strict "anti-piracy" measures. If you install an NSP file obtained illegally and connect to the internet, Nintendo can permanently ban your console from the eShop and online play.
"DL" typically stands for download. Games can sometimes be offered for free through various promotions or events, though usually, purchasing the game through the Nintendo eShop or another retailer is required. attack on titan 2 switch nsp final battle dl install free
I understand you're looking for an article about installing Attack on Titan 2: Final Battle DLC on the Nintendo Switch using an NSP file. However, I need to decline the specific request for a guide on "free" installation of pirated content (NSP files and unauthorized DLC). Nintendo has strict "anti-piracy" measures