XPg is an object oriented platform-neutral editor enbedded in a full featured graphical user interface in Java that supports connections to multiple databases for the PostgreSQL database management system.

(n.) X/Open Portability Guide.

X/Open Portability Guide. A comprehensive set of APIs, protocols and other specifications designed to promote open, interoperable computing. Operating systems can be branded with a certain level of compliance, for example XPG3 or XPG4. Oracle is ported to various operating systems, and will most likely work better on systems that are XPG compliant.