@sblionel is right. Always including E in Dw.d, Ew.d, ESw.d, or ENw.d output if w = 0 is one of the few topics on which “Modern Fortran Explained” misleads. See F2023 Tables 13.1, 13.2, and 13.3. But if w > 0 and the decimal exponent needs three digits then the E must still be omitted from the output, as already in F66 7.2.3.6.2.1 for Ew.d.