Here's an excerpt from the press release:
OCLC and Systems Planning are pleased to announce the donation of MARCView and MARConvert to OCLC, and OCLC’s release of MARCView and MARConvert as open source software under the Apache 2.0 license.
MARCView and MARConvert software, developed by Systems Planning of Bethesda, Maryland, USA, are widely-used applications designed to assist librarians and developers working with MARC records. MARCView provides a user-friendly interface to navigate and display individual MARC, MARCXML and UNIMARC records. MARConvert™ supports the conversion of bibliographic or authority records into or out of MARC21, UNIMARC or MARCXML and can also convert MARC records from one character set to another.