A new set photo from David Ayer's Suicide Squad shows that may be the files of Dr. Harleen Quinzel.

In any case, it's files from Arkham Asylum, marked for the City of Gotham Department Public Health Services.

What's interesting, perhaps, is that it appears these files are on a number of different subjects...so maybe it isn't only Harley and the Joker, but all of the Squad who have connections to Arkham.