The data and codes for this paper are available on Open ICPSR here along with a detailed README file. The paper is mainly theoretical. It solves an optimal control problem maximizing a welfare function under constraints, with the behavior of key variables being governed by an epidemiology (SEIR) model.
Following COVID, many economists used SEIR models nested in an economic model, but only a handful solved an optimal control with both testing and lockdowns as control. Relatedly, since SEIR models come in different flavors, as they are usually tweaked to fit the objectives of the paper, calculating R0 becomes quite complex. As a result, the majority of papers do not derive R0. I am attaching here a method for deriving R0 that we used, applying an approach used by mathematicians in the field. The references are in the attached document.