There are still some admin-extra related files, most confusingly, in the techproducts configset! I started up solr with -e techproducts, and saw the files listed, but couldn't use them.
While sad to see it go, I think it's better to have it be completely removed, versus still lingering about.
Related to https://issues.apache.org/jira/browse/SOLR-8140.
- is related to
SOLR-8140 Remove unfinished admin-extra support in angular UI
- links to