New XProc support site: XProcRef

XProc has a lot of built-in steps. Their functionality is described in the specification.
However, this description was aimed at XProc engine developers, not at XProc users/programmers
Hooray! There is now a website with information about the built-in XProc steps, aimed at users/programmers: XProcRef

It's still work in progress, not all steps are described yet. But what is there should already be useful. With the increasing popularity of XProc, I hope this fills a need. Have a look and let me know what you think.