Updated January 2023 by Dave Van Kleeck
You may start to see a couple of new subfields in BIB and authority records in Connexion.
Take a look at OCLC BIB# 1357120122.
In the 100, 651s, and 830 fields instead of a controlled heading in the field there is what looks like a link to the authority record.
100 1_ Pierre, Ericq, ǂd 1944- ǂe author. ǂ0 http://id.loc.gov/authorities/names/no2023002607
You may wonder, should we leave the field as is, or should we delete the link and control it?
The answer is that those links in $0 are supposed to be there and should be left as is. You may also see links in a $1 as well. Both are part of an initiative by LC and PCC to make the data in records more linked data friendly (you can see that the 042 in the record is coded “pcc”).
Apparently, there is an issue in Connexion when you try to control headings in fields with those subfields in them. While we are unsure what the status is for addressing the issue(s), we should leave the field alone and not try to control it. Supposedly if a field has a URI in one of those subfields, the heading is coming from a controlled vocabulary (in this case the NAF) so you can presume that the heading is authorized.
You may see URIs in authority records as well (often in an 024 field). This is part of the same overall initiative.
More background information in some of the LC/PCC documentation can be found here: