AP have the most comprehensive coverage of the document, which is not publicly available. Two sections in jump out to me:

“The U.S. Intelligence Community is confident in its judgment on this topic and has independently corroborated information on HAMAS and PIJ’s use of the hospital complex for a variety of purposes related to its campaign against Israel,” the assessment states. It continues that it believes the groups “used the al-Shifa hospital complex and sites beneath it to house command infrastructure, exercise certain command and control activities, store some weapons, and hold at least a few hostages.”

And

The U.S. believes that Hamas members evacuated days before Israel raided the complex on Nov. 15 and that they destroyed sensitive documents and electronics before Israeli troops entered the facility.