[out:xml][timeout:3600]; ( relation(5362856)['wikidata'='Q75648']['wikipedia'='de:Bahnstrecke Stuttgart–Tuttlingen']; way(24241726)['wikidata'='Q116817966']['wikipedia'='de:Bahnstrecke Eutingen im Gäu–Freudenstadt']; way(808515979)['wikidata'='Q18624600']['wikipedia'='de:Glaswaldsee (Naturschutzgebiet)']; ); (._;>;); out meta qt;//['wikipedia wikidata mismatch']
[out:xml][timeout:3600]; ( node(3120883520)['fixme:wikipedia'='de:Liste von Schaubergwerken']; node(3120884029)['fixme:wikipedia'='de:Liste von Schaubergwerken']; ); (._;>;); out meta qt;//['something is wrong with wikipedia tag - fixme:wikipedia is present']
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.