Probably an alt evolution.

Its its own model used for easier navigation and dimensional exploration

That really doesn't answer the question

Oh wait! So Porywalker an improved version of PorygonZ?

Yeah, I think that it would be.

It is its own line

What

The Pokemon he made.

I know, but why is it called Porygon-walker even though it's not part of the line?

Idk.