It's a reduced agitation routine, where you agitate for the first 30 seconds, then for 10 seconds at the 1, 2, 4, 8, 16 (or 15 in this case) and 32 (or 30) minute marks. Basically, you double the interval between each agitation until the development time runs out.
@tnp651 it's just another take on semi stand development. I tried it as I'm attempting to nail down development on this film. Full stand development gave me thin negatives, so i tried geometric on the next roll. Negatives were still thin, but easily scannable, so next roll I'll try a less dilute semi stand.