Warranty disclaimers, while not a part of the open source definition and not necessary for a license to function as an open source license, are nonetheless very common in licenses.

To understand the effect of the warranty disclaimer, it helps to have some understanding of what the terms used in it are and what it means to have a warranty associated with or implied by the acquisition of a particular work. The most obvious form of warranty is an express warranty . If upon the sale of a particular item, the seller explicitly states to the buyer that the item being sold, say, an answering machine, will perform a particular function, say, automatically answer incoming calls, the warranty is part of the sale. In the event the product does not perform as stated, the buyer has a remedy against the seller, generally either to have the price of purchase returned or to receive an equivalent but functioning item in exchange for the defective one. Express warranties are very common in sales of consumer goods. My stereo speakers, for example, were warrantied against defects for 10 years from the date of sale.

A warranty of merchantability is not an express warranty, but rather a variety of implied warranty , a warranty created by the operation of law, not by the seller's decision to make a particular representation. This type of warranty is generally applicable only to merchants, persons who make a business in the sale of particular goods. This warranty operates as a general guarantee ...