The myth of Leibniz’s proof of the fundamental theorem of calculus

What was Leibniz’s take on the fundamental theorem of calculus? He was one of the creators of the field after all, so one is naturally curious. But if you go to the library to find the answer to this question youwill be sold a baitand-switch. You will be referred to his 1693 article [15], supposedly the only place where Leibniz explicitly stated and proved the fundamental theorem of calculus in print. The passage in question is reproduced in full in English translation in Struik [26, pp. 282– 284], Calinger [4, pp. 354–356], Laubenbacher and Pengelley [13, pp. 133–135], discussed in full detail in Cooke [5, pp. 470–471], Hahn [11, pp. 125–128], Nitecki [25, pp. 292–293], Bressoud [3, pp. 101–102], Nauenberg [24], and cited in Katz [12, p. 529], Edwards, [8, p. 260], Volkert [27, p. 104], González-Velasco [9, p. 357], Grattan-Guinness [10, p. 55],