Yes this is the basic library that replaces powerpc.library function. Also you need to use the latest pci.library from elbox which detects your Sonnet and allows to use it.
But the are way more things that are needed for example patched RTG driver, patched chunkyppc.library, patched warp3d driver and of course every warpOS executable must be patched to call sonnet.library instead of powerpc.library. I will make article about installation for sure but once I finish my review series. Everyone who is interested in this project you can start checking apple second-hands maybe some of the powermacs includes that.
I actually don't even have a Mediator, so can't partake in these experiments

But nice to see some new work being done on the Classic PPC side. I thought I saw that Sam Jordan (WarpOS author) had resurfaced somewhat recently and was doing some new WarpOS work for another experimental project... maybe it was this one?