I submit for your perusal a video that goes in depth on the tax code and how the only thing defined as taxable income are transactions between US companies and foreign citizens or US citizens and foreign companies.

A National Income tax is unconstitutional anyways as direct taxes have to be apportioned, which is to say divided up between the states based on their population. Some say the text of Amendment 16 grants the Federal Government the right to apportion a direct tax that is not apportioned, but the Supreme Court decided in 1916 during the Stanton v. Baltic Mining, 240 U.S. 103 case that Amendment 16 conferred no new power of taxation.

So there it is for you folks, the federal income tax that we all love to pay is not only not required by the tax code, but unconstitutional.