Dominic Giampaolo developed that, so I assume that's what's being referred to.

There's a great writeup of the file system here: http://www.nobius.org/~dbg/practical-file-system-design.pdf

In particular, the labels and how they worked in BeOS are a big part of HFS, when Finder says it's "indexing" it's indexing all those extended attributes (among other things).