res files actually come from Windows and are used to translate strings for UI and errors.
Those res files are usually linked to the Windows binary.
Linux and AIX also use "res" files in a res/ directory below the binary directory.
The files are essential for a server. All the core code string resources are in strings.res.
Most Domino native servertasks also use string resources.
This is a companion discussion topic for the original entry at https://blog.nashcom.de/nashcomblog.nsf/dx/what-you-should-know-about-domino-res-files-on-linux-and-aix.htm