Hi. From http://webkitgtk.org/reference/webkit2gtk/stable/WebKitPlugin.html it says: "This object can be used to get more information about a plugin, and enable/disable it, allowing fine-grained control of plugins." Fowever, there is no way to call functions like webkit_web_plugin_get_enabled() / webkit_web_plugin_set_enabled() like there is in older WebKit1 API: http://webkitgtk.org/reference/webkitgtk/stable/WebKitWebPlugin.html
Plugins are no longer supported.