"Know tax law" in the context of a software developer I would interpret as understanding the core concepts and terminology involved in tax law, not knowing all

"Know tax law" in the context of a software developer I would interpret as understanding the core concepts and terminology involved in tax law, not knowing all the intricacies involved in every single piece of tax law. They need to be able to understand the specific pieces of tax law that they are working on with the help of an actual expert without too much friction; they don't have to be actual experts on tax law.