From the 2019 article: "... A unique Wisconsin law requires voting machine companies to place a copy of the actual vote-tabulating software in escrow after every election. Separate from the process of approving voting machines for sale, this requirement was originally intended to protect local governments’ voting-equipment investment. In case a company went out of business, the State would have a working copy of the most recently updated software as backup to keep the machines counting.

The law also requires the State to allow candidates to inspect the escrowed software if the candidates agree “to exercise the highest degree of reasonable care to maintain the confidentiality of all proprietary information.” The software in Wisconsin voting machines is the same as that used in other states, and any inspection could have national implications."