I am no coder, but I tried (failed) to make sense of the parts file format in the wiki:
2.1 Part file format · fritzing/fritzing-app Wiki · GitHub
Basically inside the .fzpz file (a.k.a. fritzing part sharable file, which is a zipped file) contains this:
[part_name].fzpz
| part.[moduleID][part_name].fzp
| svg.breadboard.[moduleID][part_name].svg
| svg.schematic.[moduleID][part_name].svg
| svg.pcb.[moduleID][part_name].svg
| svg.icon.[moduleID][part_name].svg