1964 can use any plug-in compatible with zilmar's plug-in interface specifications. This gives you the flexibility to use plug-ins from other emulators or from any plugin author who decides to use the specifications. This setting allows you to specify where the plugin folder is on your computer or network. By default the box "Use Default: $1964.exe\Plugin" is checked, meaning that 1964 will use a subfolder named Plugin in the root 1964 folder for its plug-ins. Uncheck this box and click the button to use a folder at a different location.
Fig. 1 Plugin Folder selection box