I've already looked in 2 places.
I looked in my user folder:
/Users/MYUSERNAME/Library/Screen Savers - which was empty.
(where MYUSERNAME is my user name)
I also looked in
/Library/Screen Savers/Default Collections and found images, but not the actual Screensaver configuration file itself (a .saver file, I believe):
1-National Geographic 2-Aerial 3-Cosmos 4-Nature Patterns
- But this folder only has the photos and not the Screensaver files themselves (.saver I think).
I'm particularly interested in using the Classic screen saver for the general login screen (i.e. the initial overall general start up screen where the user(s) are displayed when left unattended, not for a particular user). Once I know where this is located, I will set it to run at the login screen (for when the machine is left unattended). I believe I can set it with this guide: http://osxdaily.com/2014/03/07/set-screen-saver-login-window-mac-os-x/ (but I first of all need to know where to find the .saver file, hence my question)