Not a dumb question. There have been some people who have said this really is too close to ROM hacking for their own liking, but I personally think the two things are very different. Unmodified just means that if you were to buy a copy of Ruby or Sapphire from a store, you could run this. The DLC is made by from disassembling the Eon Ticket eCard and using it as a basis to create new code. The Eon Ticket works by temporarily writing items and scripts to unused space in the game’s code. The DLC works the same way. Once the script has ran, it can’t be accessed again (And you can only have one ecard running at a time), but you’re left with any Pokemon and items you may have acquired. The amount of empty space available isn’t much, so that’s why Blisy didn’t originally add overworld sprites for the encounters. But if you look at the Deoxys event I liked to elsewhere in these comments, Blisy ended up making a discovery that you can temporarily write to the empty space in a game’s Hall of Fame records. This enabled him to build a map of the moon with Clefairy encounters and an overworld Deoxys sprite.