There is a problem with displaying author's identifiers while OPACAuthorIdentifiersAndInformation is on for 024$2$a. At the current, the list of identifiers source is closed and hardcoded. So if it happens that in an authority record a 024 field exists with $2 from outside the list (like wikidata or other from the official list https://www.loc.gov/standards/sourcelist/standard-identifier.html), an empty bullet with no information is being displayed. This could be corrected either by filtering out the 024 fields in Koha::Authority::get_identifiers_and_information, or by correcting the template (authority-information.inc). However, this would only be a halfway solution. A more appropriate solution might be to introduce a sub-preference containing the triplets: source code ($2), label, URI prefix. E.g.: wikidata, Wikidata, http://www.wikidata.org/wiki/
Furthermore, identifiers of type "uri" in $2 (and then actual URL in $a) could be displayed as links by default (provided their scheme is http:// or https://). It's also worth pointing out that sub get_identifiers_and_information only looks into $2 and $a, meanwhile optional $1 designated for "Real World Object URI" now also exists, which could be used for fallback display/linking of unsupported identifiers if desired, moving the URL generation from the template to that function instead. It also appears that the subtest 'get_identifiers_and_information' uses $6 instead of $1 for the URI, which seems to be erroneous too.