Matteo, According to our latest chat, I believe you can mark this bug as pending. That would clarify for debian-release@l.d.o
> You seem to use libjpeg-turbo already, and openjpeg support seems to be > optional. If this can't get ported to openjpeg2 in time for Stretch, you could > drop the openjpeg support. There is no link in between libjpeg-turbo (ITU-81 standard) and openjpeg (ITU-800 standard). -M