A PKR is a Portable Component Object library. A PKR file contains binary data that can be loaded by various programs. A PKR file can be shared between two or more programs by making the necessary linkages between the shared object files. The linkages thus established to allow the programs to use the data contained in the shared object files without modification.
Shared object files have been designed for use with the Portable Shared Language (PGP) format. Portable Grammar/Text Parser (PGT) is a subset of the Portable Document Format (PDF) that was developed by Adobe Systems Incorporated and licensed for use on a PC. As its name suggests, PGP allows a document created in one program to be read by another application without modification. The Portable Document Format is used extensively in the printing industry as well as in the publishing industry and is available on a variety of portable devices.
The extension given to a PKR file is a way to uniquely identify that file for use by other applications. By using the extension PKR, it ensures that only one instance of the document will be opened when the application that needs to open it is run. An application that wishes to read a PKR must specify the appropriate extension during setup. PKR is also the commonly used file extension for newsgroup readers and other network applications.