The schematics (there are two different ones) are not so much proprietary as unsatisfactory. The original design dates from 2007 and was based on the Paramour II using its PT-2 power transformer and the Magnequest upgrade transformers. At first it was just a proof-of-concept idea, with several compromises in the design due to limitations of available components. We released a version - I'm not sure when but around 2011 I think (?) - as a beta with some notes but no actual manual, for experienced and knowledgeable builders/experimenters.
In 2014 I revised the design to use the then-new PT-7 (now PT-10) which among other things increased the shunt-reg current, which in turn required a shift to the 6DN7 as driver/shunt reg. That never went anywhere, though a few ideas went into the MonAmour. It was still unsatisfactory enough that I was reluctant to distribute the design. Somewhere around that time, PB did some work on it including the PC board.
I took one more look at it in 2014, hoping to make a fancy (expensive!) design which could use a 2A3 or a 45, had larger heat sinks and better ventilation, time delay relays for warmup, DC heaters for the DHT, etc. I still could not make a satisfactory, robust design. A few more ideas did make it into MonAmour.
That's my memory, anyhow. YMMV.