There are at least two browser extensions that do this for Wikidata: Wikidata for Web (aka Wikidata for Firefox): https://www.wikidata.org/wiki/Wikidata:Tools

There are at least two browser extensions that do this for Wikidata: Wikidata for Web (aka Wikidata for Firefox): https://www.wikidata.org/wiki/Wikidata:Tools/Wikidata_for_Web https://www.wikidata.org/wiki/Wikidata:Tools/Wikidata_for_We... and Wwwyzzerdd for Wikidata (which is by the same author as this one): https://github.com/derenrich/wwwyzzerdd https://github.com/derenrich/wwwyzzerdd The first lets you extract info from webpages and insert references for facts into Wikidata. The latter lets you formalise relationships between items mentioned in Wikipedia pages e.g. on a page for a film it might say "directed by <person>" or "based on the book <book>" and you can check if that relationship is in Wikidata and add it if not.