According to CNN, Biden’s legal team cooperated in the search. The University of Delaware Library, which has four locations in that state, has a sizable collection of papers from 1973 to 2009, in which Biden represented Delaware in the Senate. Biden is said to have added documents to that in more recent years. The papers were not publicly available.
Confidential documents were recently found in a Washington office that Biden used before he became president and in his home in Wilmington, Delaware. A beach house belonging to the president was also searched, but according to his lawyers no confidential documents were found.