[out:xml][timeout:3600]; ( node(260272663)['wikidata'='Q18625833']['wikipedia'='de:Rangendingen']; ); (._;>;); out meta qt;//['wikipedia wikidata mismatch']
[out:xml][timeout:3600]; ( node(3150676076)['information'='board']['wikipedia'='de:Gedenkstätte Eckerwald']; node(597347916)['information'='board']['wikipedia'='de:Burg Oberhohenberg']; ); (._;>;); out meta qt;//['information board with wikipedia tag, not subject:wikipedia']
[out:xml][timeout:3600]; ( way(556511180)['wikidata'!~'.*']['wikipedia'!~'.*']['wikipedia:en'='de:Hohenzollerische Landesbahn']; ); (._;>;); out meta qt;//['wikipedia tag in outdated form and there is mismatch between links']
[out:xml][timeout:3600]; ( way(24567113)['bridge:wikidata'='de:Schlichem-Viadukt']['bridge:wikipedia'='de:Schlichem-Viadukt']; ); (._;>;); out meta qt;//['bridge:wikipedia and bridge:wikidata - move to bridge outline']
JOSM Wikipedia plugin
Note to self: online version hosted at https://matkoniecz.github.io/OSM-wikipedia-tag-validator-reports, files are stored at https://github.com/matkoniecz/OSM-wikipedia-tag-validator-reports.