How to search the Library of Congress catalog?

I seem to remember that it was possible to access the Library of Congress catalog from the web search drop-down menu. The release noted for version 4.0 also announced the feature.
Yet I cannot the LOC in the web search menu any longer, nor is it in any menu AFAIK. The online manual is also silent about it when discussing web searches.

Did LOC searching/downloading disappear in v. 5.0?

I am on:
JabRef 5.0–ArchLinux–3
Linux 5.7.2-arch1-1 amd64
Java 14.0.1


it has been moved to the New Entry dialog like all other ID based fetchers (e,g, doi or ISBN)


That option does not allow searching though.

I seem to remember that in some past versions it was possble to search LOC’s catalog like the other online sources (Google scholar, etc). Or is that past-projected wishful thinking?

I looked in the code history, it’s been an id based fetcher only for the (LCCN) for at least 3 years.

But I just discovered they offer an API, so this might be an idea for an enhancement.
Feel free to open an issue at our bugtracker:

Thanks Christoph, I will.

But should I use github or discourse? You suggested the former, but this is the message I get on github when I open a new issue:

Please use the GitHub issue tracker only for bug reports and suggestions for improvements.
Feature requests, questions and general feedback is now handled at