I get it Extracts the Save game Map to be used in the other site.
But is archipelago just Randomizes the Map it gathers and use it to play a game Zelda LINK style? Japanese RPG arcade?
or It Randomizes the Map it collected and use it a MAP generation at the beginning of the Factorio game?

Archipelago in respect to Factorio takes your researches and adds them to an itempool, an itempool that can currently be filled by 11 different games. You tech tree nodes can now be filled by these "items", so you may research your own technology, or someone's A Link to the Past Hammer.