The following is from the Linux Documentation Project RPM HOWTO.
It is this database that makes RPM work the magic that it does. Stored in there are all of the properties of the installed packages. Should this become corrupted, it can be rebuilt using the rpm tool.
This link is to the RPM HOWTO - 6.
Building RPM's.
From this description, although not complex, the Luxe SDK includes a tool
that can generate a software installation pack to install a copy of all
of the files within one application's /home directory. To allow the generated
installation pack to be installed onto a production terminal, the file manifest.xml
which is part of the pack must be signed and the signature placed into a
file manifest.xml.sig and this file added to the package.