Hi, I tried to contact you by mail but I cannot find your mail address.
I see that you don't use the pluginHome api in your plugin, the goal of that api is to try to make the .jedit folder a little cleaner by setting default path to the file that plugin will store here.
I suppose that your plugin do not store files but even in that case you can add the following property in your props file
By doing that you tell jEdit that you know the pluginHome api and if you store files you will store them in the good folder.
And jEdit will be able to tell how may space is took by your plugin in the plugin manager (instead of telling "unknown")