Zenphoto version 1.6.1
When I add "example.php" and folder "example" to the plugins folder it is not discovered and not shown as available.
"Third party plugins are placed in the plugins folder and are automatically discovered."
I have tried 5 different plugins and none show as available.

TIA
-Ben

Besides that 1.6.1 is not the current version, is the plugin setup correctly? See the demo plugin for a basic setup:
https://github.com/zenphoto/demo-plugin

If it is what do the logs say?

FYI

Upgraded to 1.6.8. worked OK until I installed the demo-plugin and then the admin pages went blank. Gallery was still working. Uninstalled it and admin pages were back.

-Ben

The demo plugin is not really functional and is more a general code template to create an actual custom plugin. We'll look at why it broke the admin though.

What was in the logs regarding that?

Found it. Some backticks within a comment block were the reason. The repo has been updated.