Certain information about third party trademarks, etc. used by the seller. A notice pointing out your right, under this law, to avoid the contract for the purchase of the business opportunity within 3 business days following the signing of the contract. Of course, you should be suspicious if the seller is evasive about any answers that you need. On the other hand, you should also be wary of any verbal assurances that are not reflected in the documents themselves, especially the contract. Sometimes, unscrupulous sellers will say just about anything to make the sale.
Any contracts are especially important.
Consider getting professional advice. Many people get taken in by their own enthusiasm, and have bought business opportunities which hardly give them a chance of breaking even, much less making a profit. Most of these people really believed that they could succeed through their sincerity and hard work, but they never stepped back and thought carefully about what it would take. They promised to provide expert help in locating these cases. As it turned out, that help wasn't as expert as promised.