Robuta

https://xproc.org/specifications.html

XProc - Specifications

xproc specifications

https://www.w3.org/TR/xproc-v2-req/

XProc V2.0 Requirements

xproc requirements

https://www.w3.org/community/xproc-next/2023/03/15/still-here/

Still Here | XProc Next Community Group

still here community group xproc next