Since Pallada have valid dedicated classloader for plugin jars, old version of PLUS architecture (sharable services) will come to unworking (plugins will not see classes of other plugin, until it not depends).
Now PLUS is a library. You must add to lib plus_rt.jar, as far as you now must also add forms_rt.jar into plugin lib (otherwise, your plugin will not see properties file for localization your form).
PLUS as plugin is used only for customizing some PLUS functionaliti - for example, if you install PLUS you can control Locale for Localizer, etc. But it not required to have installed PLUS - you can use it separetelly.
Developer can get plus_rt.jar from PLUS installation, also with src.zip of PLUS API.
Access to plugin.xml as PluginDescriptor:
Easy "About Box" helper:
Helper for read options of IDEA from $IDEA_CONFIG_HOME/options/*.xml:
PLUS is available from PluginManager. It will work only with Pallada builds (becouse classloaders are now work by valid way).
TWiki documentation will be updated soon.
Thanks and hope that this make a little help for plugin deevlopers :)!