Återlunnits

Could you provide context for "återlunnits"? It does not appear as a widely recognized term in Swedish or English sources, so I want to avoid inventing incorrect information. Is it a real term in a particular field or language, a misspelling of another word, or a fictional concept you’d like me to develop in a neutral, encyclopedia-style entry? If you prefer, I can also create a concise, wiki-style article for a fictional concept named Återlunnits.