Comment 0 for bug 1780634

Many fields in bibliographic and authority records now have $1 subfields (Real world object). The idea is that URIs that describe a particular entity will go into $1, while URIs for authority records would go into the $0.

The complete list of fields that can include $1 can be found in the MARC proposal: https://www.loc.gov/marc/mac/2017/2017-08.html