MRC, Machine Readable Cataloging File (.mrc)
The MRC Misc file format
MRC files were developed in the 1960s to store bibliographic data in a machine-readable format. They are used to not only store the data but also share the records inside across libraries. It soon became the standard across the US, later expanding to Canada and eventually Europe.
Technical details of MRC files
There is a variety of records that can be contained in an MRC file, such as bibliographic, authority, community information, and more. Alternatively, MRC files can have another file extension as well. They can also be saved using the .marc extension.