Explosives are an AL2 exclusive that become available for unlock after completing the AI Robot technology tree.
They are not particularly profitable on their own though they are used to craft Ignition Systems, which have the second highest sale price of any product that is not made in a Radioactive Crafter. They are 1 of only 3 products in the AI Bomber technology tree (along with the Ignition System itself and its other primary component, the Trigger) that do not require radioactive raw materials and are crafted in traditional Crafters.
Unlike many other aspects of AL2, the Ignition System branch of the AI Bomber technology tree is similar to AL1 AI Robot production in that the production line is not particularly complex but instead relies on high quantities of resources.