"To reveal the contents" means to show or make known what is inside something, such as a box, a document, or a container. It involves uncovering or disclosing what is hidden or unknown. Full definition
Actually, it works great... you can see through it just enough to make the room feel bigger without totally revealing the contents of the closet. (domesticimperfection.com)
Current French law makes it illegal for a doctor to reveal the contents of a patient's medical records unless it is in that patient's interest. (newscientist.com)
Lots of people and companies are on Twitter these days, including Bioware, which recently revealed the contents of the upcoming Collector's Edition of Dragon Age: Origins via a link to GameStop on its Twitter feed. (randomnpc.com)