Quba 1.5.0, released June 2nd, 2025, now also supports ZUGFeRD 1 invoices and brings a search, and a manual.
Further small corrections are mentioned in the "history" section of the readme.
Quba is a reader software for electronic invoices (XRechnung, Factur-X/ZUGFeRD,
PDF, Order-X, CII or UBL).
It runs offline, is open-source and can be downloaded for free for Linux, Mac, and
Windows from it's website .