Upstream developer here. ReproZip needs to match from filename to package, not the other way around. It formerly used `dpkg-query -S FILENAME` to do this, but this was switched to reading the database directly for performance reasons (exact commit is https://github.com/ViDA-NYU/reprozip/commit/b085c41035959a451d77b0defa8c8b4ba025f47e). When many files need to be looked up, it is more efficient to do a single read through the info/*.list files than to do many such queries.
If I am missing a fast way to do this using the correct external interface, please let me know, and I will gladly update the code. A change in the database format could be a problem, thanks for letting us know. Best Rémi
