On dewiki the hovercard for Baden-Württemberg shows a strange error message as content text extract:
Hovercards makes the request https://de.wikipedia.org/w/api.php?action=query&format=json&prop=extracts|pageimages|revisions|info&redirects=true&exintro=true&exsentences=2&explaintext=true&piprop=thumbnail&pithumbsize=300&rvprop=timestamp&inprop=watched&indexpageids=true&titles=Baden-W%C3%BCrttemberg and gets the response:
{ "warnings": { "query": { "*": "Formatting of continuation data will be changing soon. To continue using the current formatting, use the 'rawcontinue' parameter. To begin using the new format, pass an empty string for 'continue' in the initial query." } }, "query": { "pageids": [ "477" ], "pages": { "477": { "pageid": 477, "ns": 0, "title": "Baden-W\u00fcrttemberg", "extract": "Die Version 0 der Seite namens \u201eBaden-W\u00fcrttemberg\u201c ist nicht vorhanden.\nDieser Fehler wird normalerweise von einem veralteten Link zur Versionsgeschichte einer Seite verursacht, die zwischenzeitlich gel\u00f6scht wurde.", "thumbnail": { "source": "https://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Locator_map_Baden-W%C3%BCrttemberg_in_Germany.svg/222px-Locator_map_Baden-W%C3%BCrttemberg_in_Germany.svg.png", "width": 222, "height": 300 }, "revisions": [ { "timestamp": "2015-03-26T07:33:13Z" } ], "contentmodel": "wikitext", "pagelanguage": "de", "touched": "2015-03-26T07:33:13Z", "lastrevid": 140282781, "length": 116825, "watched": "" } } } }