Extensions
XProc is designed to be extensible. The Working Group fully expects implementors to develop new steps in response to user demand.
The exproc.org website has been established as a place where these steps can be cataloged and, where practical, made interoperable.
The best place to discuss extension steps that you'd like to see
standardized in an interoperable way is on the
“xproc-dev
” mailing list.