At the time Red Hat Software started work on their Linux distribution, there were a number of package management systems in use, each with a different approach to making package management easier. RPP RPP was used in the first Red Hat Linux distributions. Scripts that can run before and after installation and uninstallation of packages. The files of individual packages can be checked to see that they haven't been modified since they were installed. The database of packages can be queried for information about installed packages, including file lists, descriptions and more.
Every program is made up of programming language statements stored in files.
This source code is later translated into a binary language that the computer can execute. In the case of RPP, its packages were based on source code that had been modified specifically for RPP, hence the sources weren't pristine. This is a bad idea for a number of fairly technical reasons. Not using pristine sources made it difficult for package developers to keep things straight, particularly if they were building hundreds of different packages. It couldn't guarantee executables were built from packaged sources.