The Interface window is vast in size and concise in essence: it contains just one field – Interface Language:
It doesn't take a rocket scientist to understand the meaning of this drop-down list: you can choose the language of Ringtone Creator's interface from the following:
– English (default);
– German
– Italian
– Spanish
– Russian
This list will be extended in future.
Plugins screen is a different story: it may not be available to you at all if you don't have any plugin .jar file (all plugins have the .jar file extension), or you may see the following contents:
On this picture all plugins are installed:
– Unwiredtec Sound Engine – software synthesizer supporting DLS and SF2 sound banks;
– Unwiredtec Impression Engine – Macromedia Flash® ringtone preview generator for Ringtone Creator;
– RingT1 XML Data Feed – plugin for creation of XML data feeds for 
RingT1 search engine