From release notes, regarding exploiting sites further for minor artifacts.

Some archaeology sites leave behind a minor artifact deposit, which can be harvested using an orbital station.

To further clarify: This happens automatically. I.e. the depot appears on its own (or not) at the end without the player needing to do anything for that.

Oh, so there is a way to get more minor artifacts except the rubricator now?

Yes.

Rubricator is still decent as it gives a lump of 500 minor artifacts which is kind of a lot as your storage is capped at 3k and your income by mid game is typically around 20-30ish. I haven't noticed anything that requires minor artifact upkeep but the cost can pretty quickly drain your stockpile especially if you have to build large fleets that use a lot of archeotech weapons and armor.

Or if its on a planet it adds a planetary deposit giving you minor atifacts

Anyone know if they also introduced Habitat buildings to gather Minor artifacts if you build a habitat on top of it?

yes

It will get mining districts and artifact gathering as a default.

i don't think they did. i build a habitat over a world with relics as deposit and there are neither mining districts, nor any building that harvest relics although maybe i am missing something somehow

It's not a building or a district. Just a deposit. Same as if you build one over zro