MSI, Inno and NSIS installers are automatically detected (also if they are nested by ExeInZip). Others can specify command line switches in the rapps-db package.
DelRegEmpty exists to clean up "company" registry parent keys. If another application is writing to the key at the same time as we are gently trying to remove it, our uninstaller should ignore any errors.
With a single database line added to applications distributed as zip/cab allows rapps.exe to act as an installer that automatically extracts the files and creates a startmenu shortcut. It can also uninstall the extracted files (and optionally other files and registry entries created by the application).