The Mütter Museum of the College of Physicians of Philadelphia has cataloged human remains after consulting with relevant Native American groups and determined there is a connection between these remains and present-day tribes. They invite tribes not listed in the document to request the transfer of remains by March 11, 2021, if they believe they are affiliated. The remains were historically linked to a Sioux Indian prisoner at Rock Island Arsenal, Illinois, dating back to the 19th century. If no new requests are received by the deadline, the remains' transfer to the identified tribes will proceed.
Simple Explanation
The Mütter Museum in Philadelphia found some old bones and talked to Native American groups to see who they belong to. If no other groups ask for the bones by March 11, 2021, they'll give them back to the tribes they already talked to.