[en] Measurements at the Livermore electron beam ion trap have been performed in order to infer the energy and the radiative lifetime of the ${(1s^{2}2s^{2}2p_{1/2}^{5}3s_{1/2})}_{J=0}$ level in the Fe xvii spectrum. This is the longest-lived level in the neonlike iron ion, and its radiative decay produces the Fe xvii line at 1153 Å, feeding the population of the ${(1s^{2}2s^{2}2p_{3/2}^{5}3s_{1/2})}_{J=1}$ upper level of one of the most prominent lines in the Fe xvii L-shell X-ray spectrum, commonly dubbed $3G$. In the presence of a strong ($⩾<!--\; ???\; -->$ few kG) magnetic field, the ${(1s^{2}2s^{2}2p_{1/2}^{5}3s_{1/2})}_{J=0}$ level has a finite probability to decay directly to the ${(1s^{2}2s^{2}2p^6)}_{J=0}$ neonlike ground level via the emission of an L-shell X-ray. Our measurements allow us to observe this X-ray line in the Fe xvii L-shell spectrum and from it to infer the radiative rate for the magnetic dipole decay of the ${(1s^{2}2s^{2}2p_{1/2}^{5}3s_{1/2})}_{J=0}$ level to the ${(1s^{2}2s^{2}2p_{3/2}^{5}3s_{1/2})}_{J=1}$. Our result of $(1.45\pm <!--\; ??\; -->0.15)\times <!--\; ??\; -->{10}^4$ s⁻¹ is in agreement with predictions. We have also measured the wavelength of the associated X-ray line to be 16.804 ± 0.002 Å, which means that the line is displaced 1.20 ± 0.05 eV from the neighboring ${(2s^{2}2p_{1/2}^{5}3s_{1/2})}_{J=1}\to <!--\; ???\; -->{(2s^{2}2p^6)}_{J=0}$ transition, commonly labeled $3F$. From our measurement, we infer 5950570 ± 710 cm⁻¹ for the energy of the ${(1s^{2}2s^{2}2p_{1/2}^{5}3s_{1/2})}_{J=0}$ level.