For wikidata, there exists a resolver at https://tools.wmflabs.org/wikidata-todo/resolver.php, which allows me to build URLs such as
https://tools.wmflabs.org/wikidata-todo/resolver.php?quick=VIAF:12307054 , or https://tools.wmflabs.org/wikidata-todo/resolver.php?prop=P227&value=120...
in order to address wikidata items directly from their external identifiers.
Squid is more appealing for viewing the items. Does a similar mechanism exist there?
Cheers, Joachim