mantragora
BTW. I didn't even used there vectors stored in array, because I don't see them used anywhere in attached image. It seems to just test array size, generate new array of numbers from 0-arraysize(), divides it and use it as U value. And that's it. No vector reading from original array.
Well, it is an array, you should believe me

Exactly is an array of locations, (relative coordinate interplated between points), from there you'll get point position or any else existing attribute. I intentionally made a screenshot of tooltip. But yeah, because of node polymorphism, you know that there is an array, only by tooltip, or by red node if trying to drive the wrong context (similar to attribute class in H), or, by what is plugged into port - that ‘invisibility’ is not a nice point, imho.
Wouldn't hurt to see the extension of work on array nodes in H15, already started in H14. It's not only geo querry in ICE, able to process an array - it is also a bunch of curve creation nodes ( I mean, ‘virtual’ curve). Or, feeding a random array into ray direction of ICE raycast (H intersect), creates a sort of ambient occlusion effect. And so on.