[out:xml][timeout:3600]; ( way(1186579025)['wikidata'='Q1187934']['wikipedia'='de:Denkershäuser Teich']; ); (._;>;); out meta qt;//['wikipedia wikidata mismatch']
[out:xml][timeout:3600]; ( node(2707550338)['information'='board']['wikipedia'='de:Burg Hunnesrück']; ); (._;>;); out meta qt;//['information board with wikipedia tag, not subject:wikipedia']
[out:xml][timeout:3600]; ( way(195293262)['brand:wikidata'='Q14751117']['not:brand:wikidata'='Q14751117']; ); (._;>;); out meta qt;//['wikipedia/wikidata type tag that is incorrect according to not:* tag']
[out:xml][timeout:3600]; ( node(5126058638)['operator:wikidata'='Q541030']['operator:wikipedia'='de:DPDgroup']; way(623112476)['operator:wikidata'='Q541030']['operator:wikipedia'='de:DPDgroup']; ); (._;>;); out meta qt;//['wikipedia wikidata mismatch - for operator prefixed tags']
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.