[Therion] Survey altitude in debuggable format

Is there some kind of debug output that I can get from Therion which will tell me the altitudes that it picked for its automatic colour bands (for "color map-fg altitude")? Obviously, I can see these visually on a PDF, but those numbers are rounded (I don't know if Therion actually picks "4" or "4.253" as the actual boundary), and I was hoping they might be in a format that is more easily machine readable. Perhaps something in thTMPDIR? Thanks for any info.