Some plugins are supposed to be tested and working and live in ../src/plugins/
-These aren't (yet).
+These aren't yet. Or, in the case of old/*, they're
+sort-of-abandoned, and only kept around in case anyone wants to adopt
+them and bring them back to stability.
Feel free to check
https://fusionforge.org/plugins/mediawiki/wiki/fusionforge/index.php/Plugins