Not sure if it's still the case but Ghostscript is or was like this - a licenseable current version possibly with extra commercially relevant features (e.g. PCL

Not sure if it's still the case but Ghostscript is or was like this - a licenseable current version possibly with extra commercially relevant features (e.g. PCL) plus an open source older version. Edit: https://artifex.com/licensing/commercial/ https://artifex.com/licensing/commercial/ notably this lets you avoid concerns about integrating GPL with your commercial offering.