Leak of over a hundred classified Pentagon documents is very embarrassing for the United States. One document describes South Korea's – until now – secret plans to send ammunition to Ukraine.
Another appears to be a map of, among other things, Ukraine's defense against air strikes, dated March 1, 40 days ago. If authentic, as seems likely, the documents could give Russia insight into details of Ukraine's defenses that it had not previously been aware of, and clues about Ukraine's military planning going forward.