I have a question. Is it possible to merge a PDF and a XML file with Mustang Project ? My goal is to have a PDF/A-3
Sorry for the late answer. This was a test and since it did not get used in the first weeks I'll close it. But yes, that's possible, on command line with -c https://mustangproject.org/use/#combine and in the library with setZUGFeRDXMLData https://mustangproject.org/use/#custom . You only need a PDF/A (-1 or -3), if you have a normal PDF only you could consider e.g. ghostscript to convert.