I’ve been looking for a description of what the different label numbers refer to but so far I’ve found nothing. For the moment I’m assuming the “76” refers to the Prison Camp number while the roman numerals “XVII” indicate the German Army Corps District, in this case Danzig. The Wiki page lists two camps in district XVII: Czersk and Danzig (Troyl). I thought the number in the lower right corner might be the individual Prisoner number.
I’m sure someone out there knows exactly how to read these labels and I’m hoping they pass along their knowledge.