I spoke to Jamis Buck on Twitter. It’s called “Randomized Prim’s” on Wikipedia [1], but of course Wikipedia is not authoritative. It does seem confusing to call it a variant of Prim’s given how different the behavior is.
I see -- apparently it's common to call this "Prim's algorithm" even though it is more accurately described as a randomized variant of breadth/depth-first search. Thanks for clarifying that.
I do still object to the text reading "This article is about using another minimal spanning tree algorithm to do the same" -- what is described there is not a minimal spanning tree algorithm (even if it's called Prim's algorithm).
[1] http://en.wikipedia.org/wiki/Maze_generation_algorithm#Rando...