Is there any system wide folder reaper checks for UserPlugins like sws?
Many people install it via their distributions and don't wanna link it manually to ~/.config/REAPER/UserPlugins.
See
https://aur.archlinux.org/packages/sws/
"I have the same problem as UlrichH, a symlink to /usr/lib/REAPER/Plugins/reaper_sws64.so needed in ~/.config/REAPER/UserPlugins/ for Reaper to see the SWS extensions."