MARC, Machine Readable Cataloging File (.marc)
The MARC Misc file format
Files stored with the extension MARC are known for storing machine-readable text that contains bibliographic information. It was developed back in the 1960s by Henriette Avram when working with the Library of Congress. During the 1970s, it became the standard file format used in the US to store and use bibliographic data. It's used to store and share records among different libraries.
Technical details of MARC files
MARC files are used for a variety of records, such as authority, bibliographic, community information, and other records across the US, Canada, and with the introduction of UNIMARC, also in Europe. Files can alternatively also use the file extension MRC instead of storing files with the .marc extension.